Hakan Orer - Academia.edu (original) (raw)
Papers by Hakan Orer
Journal of Neurophysiology, 1995
1. This is the first study to map the axonal projections of medullary neurons that are elements o... more 1. This is the first study to map the axonal projections of medullary neurons that are elements of the network responsible for the 10-Hz rhythm in sympathetic nerve discharge (SND) of urethan-anesthetized cats. Spike-triggered averaging and coherence analysis were used to identify caudal ventrolateral medullary (CVLM) and medullary raphe neurons with activity correlated to this component of SND. Spike-triggered averaging showed that CVLM neurons fired significantly earlier (17 ms on the average) than raphe neurons during the 10-Hz slow wave in inferior cardiac postganglionic SND. This observation raised the possibility that CVLM neurons are a source of the discharges of raphe neurons that are correlated to SND. 2. Nineteen of 47 CVLM neurons with activity correlated to the 10-Hz rhythm in SND were antidromically activated by micro-stimulation of the raphe. The longest onset latency of antidromic activation was 19.9 +/- 2.8 (SE) ms, a value comparable with the difference in firing ti...
American Journal of Physiology-Heart and Circulatory Physiology, 2001
This study was designed to test the hypothesis that 8-hydroxy-2-(di- n-propylamino)tetralin (8-OH... more This study was designed to test the hypothesis that 8-hydroxy-2-(di- n-propylamino)tetralin (8-OHDPAT) and clonidine reduce sympathetic nerve discharge (SND) and mean arterial pressure (MAP), in part by actions in the medullary lateral tegmental field (LTF). We microinjected these drugs bilaterally into the LTF of baroreceptor-innervated and -denervated cats anesthetized with Dial-urethane. Neither drug altered SND (as quantified by using power spectral analysis) or MAP when injected into the LTF of baroreceptor-denervated cats. However, cardiac-related power in SND was significantly increased to 148 ± 12 (mean ± SE) and 149 ± 5% of control by microinjections of 8-OHDPAT ( n = 5) and clonidine ( n = 5), respectively, in baroreceptor-innervated cats whose MAP was kept constant; there was no change in 0- to 6-Hz power or total power. SND was significantly reduced by microinjection of these drugs into the rostral ventrolateral medulla of baroreceptor-innervated and -denervated cats. In...
American Journal of Physiology-Heart and Circulatory Physiology, 2017
Serotonin [5-hydroxytryptamine (5-HT)] causes relaxation of the isolated superior mesenteric vein... more Serotonin [5-hydroxytryptamine (5-HT)] causes relaxation of the isolated superior mesenteric vein, a splanchnic blood vessel, through activation of the 5-HT7 receptor. As part of studies designed to identify the mechanism(s) through which chronic (≥24 h) infusion of 5-HT lowers blood pressure, we tested the hypothesis that 5-HT causes in vitro and in vivo splanchnic venodilation that is 5-HT7 receptor dependent. In tissue baths for measurement of isometric contraction, the portal vein and abdominal inferior vena cava relaxed to 5-HT and the 5-HT1/7 receptor agonist 5-carboxamidotryptamine; relaxation was abolished by the 5-HT7 receptor antagonist SB-269970. Western blot analyses showed that the abdominal inferior vena cava and portal vein express 5-HT7 receptor protein. In contrast, the thoracic vena cava, outside the splanchnic circulation, did not relax to serotonergic agonists and exhibited minimal expression of the 5-HT7 receptor. Male Sprague-Dawley rats with chronically implan...
Journal of Neurophysiology
ABSTRACT
Pediatric Research, 2003
Hypotensive episodes are frequent during pregnancy, and their functional effect on fetal brain ha... more Hypotensive episodes are frequent during pregnancy, and their functional effect on fetal brain has not been studied. We produced systemic hypotension for 30 min during mid-gestation in pregnant rats and examined their offspring on postnatal days 1 and 28. When compared with sham controls, the brain of the hypotensive group contained more TUNEL-positive cells in the hippocampal and periventricular regions on both time points. Spatial learning assessed by water milk maze test was impaired in 28-day-old pups of the hypotensive mothers. According to these results, transient maternal hypotension can induce apoptotic cell death in fetal brain and affect learning. Similar mechanisms may be considered and investigated in the pathogenesis of human learning disorders. (Pediatr Res 53: 977-982, 2003) Abbreviations MBP, mean blood pressure HR, heart rate NC, newborn control group NH, newborn, hypotension group PVGZ, periventricular germinative zone YC, young control group YH, young, hypotension group WMM, water milk maze test
Journal of Neurophysiology, 2005
We used Allan factor analysis to classify time series of the discharges of single presympathetic ... more We used Allan factor analysis to classify time series of the discharges of single presympathetic neurons in the cat medullary lateral tegmental field (LTF) and rostral ventrolateral medulla (RVLM) and of the postganglionic vertebral sympathetic nerve. These time series fell into two classes of fractal-based point processes characterized by statistically self-similar behavior reflecting long-range correlations among data points. Classification of a time series as either a fractional Gaussian noise (fGn)–or fractional Brownian motion (fBm)–based point process depended on the scaling exponent, α, of the power law in the Allan factor curve. fGn is defined as 0 < α < 1 and fBm as 1 < α < 3. The process responsible for the fractal spike trains of 11 of 12 classifiable LTF neurons with sympathetic nerve-related activity was fGn. In contrast, the process responsible for the fractal spike trains of eight of nine classifiable RVLM presympathetic neurons was fBm. The time series of...
Journal of Applied Physiology, 2006
In an effort to characterize the role of the medullary lateral tegmental field (LTF) in regulatin... more In an effort to characterize the role of the medullary lateral tegmental field (LTF) in regulating respiration, we tested the effects of selective blockade of excitatory (EAA) and inhibitory amino acid (IAA) receptors in this region on phrenic nerve activity (PNA) of vagus-intact and vagotomized cats anesthetized with dial-urethane. We found distinct patterns of changes in central respiratory rate, duration of inspiratory and expiratory phases of PNA (Ti and Te, respectively), and I-burst amplitude after selective blockade of EAA and IAA receptors in the LTF. First, blockade of N-methyl-d-aspartate (NMDA) receptors significantly ( P < 0.05) decreased central respiratory rate primarily by increasing Ti but did not alter I-burst amplitude. Second, blockade of non-NMDA receptors significantly reduced I-burst amplitude without affecting central respiratory rate. Third, blockade of GABAAreceptors significantly decreased central respiratory rate by increasing Te and significantly reduc...
European Journal of Pharmacology, 1990
Brain Research, 1995
In urethane-anesthetized cats, ordinary and partial coherence values relating the 10-Hz rhythmic ... more In urethane-anesthetized cats, ordinary and partial coherence values relating the 10-Hz rhythmic discharges of sympathetic nerves located on opposite sides of the body were not significantly affected by midsagittal section of the spinal cord from the seventh cervical through eighth thoracic or first cervical through eighth cervical segments. Thus, coordination of the 10-Hz discharges of the nerves occurred at a supraspinal level.
American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 2010
This study was designed to build on past work from this laboratory by testing the hypothesis that... more This study was designed to build on past work from this laboratory by testing the hypothesis that medullary lateral tegmental field (LTF) neurons play a critical role in mediating sympathoexcitatory responses to activation of sympathetic afferent fibers. We studied the effects of microinjection of N-methyl-d-aspartate (NMDA) or non-NMDA receptor antagonists or muscimol bilaterally into the LTF on the area under the curve of the computer-averaged sympathoexcitatory potential in the right inferior cardiac nerve elicited by short trains of stimuli applied to afferent fibers in the left inferior cardiac or left splanchnic nerve (CN, SN) of baroreceptor-denervated and vagotomized cats anesthetized with a mixture of diallylbarbiturate and urethane. In contrast to our hypothesis, sympathoexcitatory responses to stimulation of CN ( n = 5–7) or SN ( n = 4–7) afferent fibers were not significantly affected by these procedures. We then determined whether the rostral and caudal ventrolateral me...
Turkiye Klinikleri Journal of Hematology Special Topics, 2014
Biochemistry and Molecular Biology Education, 2020
A vibrant and sustainable research environment is essential to establish a thriving PhD program. ... more A vibrant and sustainable research environment is essential to establish a thriving PhD program. Organization for PhD Education in Health Sciences in European System, a European platform to promote best practices in PhD education in health sciences, published a guideline entitled "Best Practices for PhD Training." The guideline includes comprehensive recommendations and suggestions on different components of the PhD program, of which supervision is an essential one. A working supervisor-student relationship based on mutual respect, responsibility, and participation is essential for the success of a PhD thesis. Supervisors should be active researchers and receive training to develop their supervising skills. They serve as role models in academic life, both scientifically and ethically. The appointment of a co-supervisor, besides the principal one, is strongly encouraged not only to increase the efficiency in
American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 1996
We studied the effects of serotonin (5-HT)-receptor agonists and antagonists on the naturally occ... more We studied the effects of serotonin (5-HT)-receptor agonists and antagonists on the naturally occurring 10-Hz rhythm in sympathetic nerve discharge (SND) of urethan-anesthetized, baroreceptor-denervated cats. Intravenous doses of the 5-HT1A-receptor agonists 8-hydroxy-2(di-n-propylamino)-tetralin (8-OH-DPAT) and U-93385E, which inhibit the firing of serotonergic medullary raphe neurons, decreased the power in the 10-Hz band of SND without affecting the power at frequencies < or = 6 Hz. The inhibitory effects of 8-OH-DPAT and U-93385E were reversed by the 5-HT1A-receptor antagonists spiperone and WAY-100135. Microinjection of 8-OH-DPAT into medullary raphe nuclei also selectively eliminated the 10-Hz rhythm in SND. Intravenous administration of the 5-HT2-receptor antagonist methysergide blocked the 10-Hz rhythm in SND, whereas the 5-HT2-receptor agonist 1-(2,5-dimethoxy-4-iodophenyl)-2-amino-propane increased peak frequency and power in the 10-Hz band of SND. Microinjection of N-m...
American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 1996
We studied the effects of adrenoceptor agonists and antagonists on sympathetic nerve discharge (S... more We studied the effects of adrenoceptor agonists and antagonists on sympathetic nerve discharge (SND) of urethan-anesthetized, baroreceptor-denervated cats. In cats in which a 10-Hz rhythm coexisted with irregular 2- to 6-Hz oscillations in SND, intravenous clonidine, an alpha 2-adrenoceptor agonist, blocked the 10-Hz rhythm without affecting power at lower frequencies. In contrast, power at frequencies < or = 6 Hz was depressed by clonidine in cats in which the 10-Hz rhythm was absent. These effects were reversed by intravenous administration of alpha 2-adrenoceptor antagonists, idazoxan and rauwolscine. Rauwolscine is devoid of affinity for imidazoline receptors. Furthermore, in cats untreated with clonidine, idazoxan and rauwolscine enhanced or induced the 10-Hz rhythm without affecting power at lower frequencies. Prazosin, an alpha 1-adrenoceptor antagonist, selectively blocked the 10-Hz rhythm in SND. Finally, the 10-Hz rhythm in SND was blocked by microinjection of clonidine...
American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 1994
Partial coherence analysis was used to remove the influences of pulse-synchronous baroreceptor ne... more Partial coherence analysis was used to remove the influences of pulse-synchronous baroreceptor nerve activity (as reflected by the arterial pulse) on the coherence of the cardiac-related discharges of sympathetic nerve pairs in unanesthetized decerebrate cats. It can be predicted that the peak at the heart rate frequency in the ordinary coherence function relating the discharges of two nerves will be eliminated by either partialization using the arterial pulse or surgical baroreceptor denervation, if the central circuits controlling the nerves share baroreceptor inputs but are not interconnected. Contrary to this prediction, in many experiments the peak was not eliminated by partialization using the arterial pulse. Moreover, partialization often nonuniformly reduced the peaks at the heart rate frequency in the coherence functions for different nerve pairs. These results are consistent with a model of multiple routes over which baroreceptor influences are distributed to the central c...
American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 2000
We used blockade of excitatory amino acid (EAA) neurotransmission in the medullary lateral tegmen... more We used blockade of excitatory amino acid (EAA) neurotransmission in the medullary lateral tegmental field (LTF) and rostral ventrolateral medulla (RVLM) to assess the roles of these regions in the control of inferior cardiac sympathetic nerve discharge (SND) and mean arterial pressure (MAP) in urethan-anesthetized, baroreceptor-denervated cats. Bilateral microinjection of a non- N-methyl-d-aspartate (NMDA)-receptor antagonist [1,2,3,4-tetrahydro-6-nitro-2,3-dioxobenzo-[f]quinoxaline-7-sulfonamide (NBQX)] into the LTF significantly decreased SND to 46 ± 4% of control (as demonstrated with power-density spectral analysis) and MAP by 16 ± 6 mmHg. In contrast, bilateral microinjection of an NMDA-receptor antagonist [d(−)-2-amino-5-phosphonopentanoic acid (d-AP5)] into the LTF did not decrease SND or MAP. These results demonstrate that the LTF is an important synaptic relay in the pathway responsible for basal SND in the cat. Bilateral microinjection of NBQX or d-AP5 into the RVLM signi...
Turkish Journal of Biochemistry, 2018
Turkiye Klinikleri Journal of Case Reports, 1990
Journal of Neurophysiology, 1995
1. This is the first study to map the axonal projections of medullary neurons that are elements o... more 1. This is the first study to map the axonal projections of medullary neurons that are elements of the network responsible for the 10-Hz rhythm in sympathetic nerve discharge (SND) of urethan-anesthetized cats. Spike-triggered averaging and coherence analysis were used to identify caudal ventrolateral medullary (CVLM) and medullary raphe neurons with activity correlated to this component of SND. Spike-triggered averaging showed that CVLM neurons fired significantly earlier (17 ms on the average) than raphe neurons during the 10-Hz slow wave in inferior cardiac postganglionic SND. This observation raised the possibility that CVLM neurons are a source of the discharges of raphe neurons that are correlated to SND. 2. Nineteen of 47 CVLM neurons with activity correlated to the 10-Hz rhythm in SND were antidromically activated by micro-stimulation of the raphe. The longest onset latency of antidromic activation was 19.9 +/- 2.8 (SE) ms, a value comparable with the difference in firing ti...
American Journal of Physiology-Heart and Circulatory Physiology, 2001
This study was designed to test the hypothesis that 8-hydroxy-2-(di- n-propylamino)tetralin (8-OH... more This study was designed to test the hypothesis that 8-hydroxy-2-(di- n-propylamino)tetralin (8-OHDPAT) and clonidine reduce sympathetic nerve discharge (SND) and mean arterial pressure (MAP), in part by actions in the medullary lateral tegmental field (LTF). We microinjected these drugs bilaterally into the LTF of baroreceptor-innervated and -denervated cats anesthetized with Dial-urethane. Neither drug altered SND (as quantified by using power spectral analysis) or MAP when injected into the LTF of baroreceptor-denervated cats. However, cardiac-related power in SND was significantly increased to 148 ± 12 (mean ± SE) and 149 ± 5% of control by microinjections of 8-OHDPAT ( n = 5) and clonidine ( n = 5), respectively, in baroreceptor-innervated cats whose MAP was kept constant; there was no change in 0- to 6-Hz power or total power. SND was significantly reduced by microinjection of these drugs into the rostral ventrolateral medulla of baroreceptor-innervated and -denervated cats. In...
American Journal of Physiology-Heart and Circulatory Physiology, 2017
Serotonin [5-hydroxytryptamine (5-HT)] causes relaxation of the isolated superior mesenteric vein... more Serotonin [5-hydroxytryptamine (5-HT)] causes relaxation of the isolated superior mesenteric vein, a splanchnic blood vessel, through activation of the 5-HT7 receptor. As part of studies designed to identify the mechanism(s) through which chronic (≥24 h) infusion of 5-HT lowers blood pressure, we tested the hypothesis that 5-HT causes in vitro and in vivo splanchnic venodilation that is 5-HT7 receptor dependent. In tissue baths for measurement of isometric contraction, the portal vein and abdominal inferior vena cava relaxed to 5-HT and the 5-HT1/7 receptor agonist 5-carboxamidotryptamine; relaxation was abolished by the 5-HT7 receptor antagonist SB-269970. Western blot analyses showed that the abdominal inferior vena cava and portal vein express 5-HT7 receptor protein. In contrast, the thoracic vena cava, outside the splanchnic circulation, did not relax to serotonergic agonists and exhibited minimal expression of the 5-HT7 receptor. Male Sprague-Dawley rats with chronically implan...
Journal of Neurophysiology
ABSTRACT
Pediatric Research, 2003
Hypotensive episodes are frequent during pregnancy, and their functional effect on fetal brain ha... more Hypotensive episodes are frequent during pregnancy, and their functional effect on fetal brain has not been studied. We produced systemic hypotension for 30 min during mid-gestation in pregnant rats and examined their offspring on postnatal days 1 and 28. When compared with sham controls, the brain of the hypotensive group contained more TUNEL-positive cells in the hippocampal and periventricular regions on both time points. Spatial learning assessed by water milk maze test was impaired in 28-day-old pups of the hypotensive mothers. According to these results, transient maternal hypotension can induce apoptotic cell death in fetal brain and affect learning. Similar mechanisms may be considered and investigated in the pathogenesis of human learning disorders. (Pediatr Res 53: 977-982, 2003) Abbreviations MBP, mean blood pressure HR, heart rate NC, newborn control group NH, newborn, hypotension group PVGZ, periventricular germinative zone YC, young control group YH, young, hypotension group WMM, water milk maze test
Journal of Neurophysiology, 2005
We used Allan factor analysis to classify time series of the discharges of single presympathetic ... more We used Allan factor analysis to classify time series of the discharges of single presympathetic neurons in the cat medullary lateral tegmental field (LTF) and rostral ventrolateral medulla (RVLM) and of the postganglionic vertebral sympathetic nerve. These time series fell into two classes of fractal-based point processes characterized by statistically self-similar behavior reflecting long-range correlations among data points. Classification of a time series as either a fractional Gaussian noise (fGn)–or fractional Brownian motion (fBm)–based point process depended on the scaling exponent, α, of the power law in the Allan factor curve. fGn is defined as 0 < α < 1 and fBm as 1 < α < 3. The process responsible for the fractal spike trains of 11 of 12 classifiable LTF neurons with sympathetic nerve-related activity was fGn. In contrast, the process responsible for the fractal spike trains of eight of nine classifiable RVLM presympathetic neurons was fBm. The time series of...
Journal of Applied Physiology, 2006
In an effort to characterize the role of the medullary lateral tegmental field (LTF) in regulatin... more In an effort to characterize the role of the medullary lateral tegmental field (LTF) in regulating respiration, we tested the effects of selective blockade of excitatory (EAA) and inhibitory amino acid (IAA) receptors in this region on phrenic nerve activity (PNA) of vagus-intact and vagotomized cats anesthetized with dial-urethane. We found distinct patterns of changes in central respiratory rate, duration of inspiratory and expiratory phases of PNA (Ti and Te, respectively), and I-burst amplitude after selective blockade of EAA and IAA receptors in the LTF. First, blockade of N-methyl-d-aspartate (NMDA) receptors significantly ( P < 0.05) decreased central respiratory rate primarily by increasing Ti but did not alter I-burst amplitude. Second, blockade of non-NMDA receptors significantly reduced I-burst amplitude without affecting central respiratory rate. Third, blockade of GABAAreceptors significantly decreased central respiratory rate by increasing Te and significantly reduc...
European Journal of Pharmacology, 1990
Brain Research, 1995
In urethane-anesthetized cats, ordinary and partial coherence values relating the 10-Hz rhythmic ... more In urethane-anesthetized cats, ordinary and partial coherence values relating the 10-Hz rhythmic discharges of sympathetic nerves located on opposite sides of the body were not significantly affected by midsagittal section of the spinal cord from the seventh cervical through eighth thoracic or first cervical through eighth cervical segments. Thus, coordination of the 10-Hz discharges of the nerves occurred at a supraspinal level.
American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 2010
This study was designed to build on past work from this laboratory by testing the hypothesis that... more This study was designed to build on past work from this laboratory by testing the hypothesis that medullary lateral tegmental field (LTF) neurons play a critical role in mediating sympathoexcitatory responses to activation of sympathetic afferent fibers. We studied the effects of microinjection of N-methyl-d-aspartate (NMDA) or non-NMDA receptor antagonists or muscimol bilaterally into the LTF on the area under the curve of the computer-averaged sympathoexcitatory potential in the right inferior cardiac nerve elicited by short trains of stimuli applied to afferent fibers in the left inferior cardiac or left splanchnic nerve (CN, SN) of baroreceptor-denervated and vagotomized cats anesthetized with a mixture of diallylbarbiturate and urethane. In contrast to our hypothesis, sympathoexcitatory responses to stimulation of CN ( n = 5–7) or SN ( n = 4–7) afferent fibers were not significantly affected by these procedures. We then determined whether the rostral and caudal ventrolateral me...
Turkiye Klinikleri Journal of Hematology Special Topics, 2014
Biochemistry and Molecular Biology Education, 2020
A vibrant and sustainable research environment is essential to establish a thriving PhD program. ... more A vibrant and sustainable research environment is essential to establish a thriving PhD program. Organization for PhD Education in Health Sciences in European System, a European platform to promote best practices in PhD education in health sciences, published a guideline entitled "Best Practices for PhD Training." The guideline includes comprehensive recommendations and suggestions on different components of the PhD program, of which supervision is an essential one. A working supervisor-student relationship based on mutual respect, responsibility, and participation is essential for the success of a PhD thesis. Supervisors should be active researchers and receive training to develop their supervising skills. They serve as role models in academic life, both scientifically and ethically. The appointment of a co-supervisor, besides the principal one, is strongly encouraged not only to increase the efficiency in
American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 1996
We studied the effects of serotonin (5-HT)-receptor agonists and antagonists on the naturally occ... more We studied the effects of serotonin (5-HT)-receptor agonists and antagonists on the naturally occurring 10-Hz rhythm in sympathetic nerve discharge (SND) of urethan-anesthetized, baroreceptor-denervated cats. Intravenous doses of the 5-HT1A-receptor agonists 8-hydroxy-2(di-n-propylamino)-tetralin (8-OH-DPAT) and U-93385E, which inhibit the firing of serotonergic medullary raphe neurons, decreased the power in the 10-Hz band of SND without affecting the power at frequencies < or = 6 Hz. The inhibitory effects of 8-OH-DPAT and U-93385E were reversed by the 5-HT1A-receptor antagonists spiperone and WAY-100135. Microinjection of 8-OH-DPAT into medullary raphe nuclei also selectively eliminated the 10-Hz rhythm in SND. Intravenous administration of the 5-HT2-receptor antagonist methysergide blocked the 10-Hz rhythm in SND, whereas the 5-HT2-receptor agonist 1-(2,5-dimethoxy-4-iodophenyl)-2-amino-propane increased peak frequency and power in the 10-Hz band of SND. Microinjection of N-m...
American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 1996
We studied the effects of adrenoceptor agonists and antagonists on sympathetic nerve discharge (S... more We studied the effects of adrenoceptor agonists and antagonists on sympathetic nerve discharge (SND) of urethan-anesthetized, baroreceptor-denervated cats. In cats in which a 10-Hz rhythm coexisted with irregular 2- to 6-Hz oscillations in SND, intravenous clonidine, an alpha 2-adrenoceptor agonist, blocked the 10-Hz rhythm without affecting power at lower frequencies. In contrast, power at frequencies < or = 6 Hz was depressed by clonidine in cats in which the 10-Hz rhythm was absent. These effects were reversed by intravenous administration of alpha 2-adrenoceptor antagonists, idazoxan and rauwolscine. Rauwolscine is devoid of affinity for imidazoline receptors. Furthermore, in cats untreated with clonidine, idazoxan and rauwolscine enhanced or induced the 10-Hz rhythm without affecting power at lower frequencies. Prazosin, an alpha 1-adrenoceptor antagonist, selectively blocked the 10-Hz rhythm in SND. Finally, the 10-Hz rhythm in SND was blocked by microinjection of clonidine...
American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 1994
Partial coherence analysis was used to remove the influences of pulse-synchronous baroreceptor ne... more Partial coherence analysis was used to remove the influences of pulse-synchronous baroreceptor nerve activity (as reflected by the arterial pulse) on the coherence of the cardiac-related discharges of sympathetic nerve pairs in unanesthetized decerebrate cats. It can be predicted that the peak at the heart rate frequency in the ordinary coherence function relating the discharges of two nerves will be eliminated by either partialization using the arterial pulse or surgical baroreceptor denervation, if the central circuits controlling the nerves share baroreceptor inputs but are not interconnected. Contrary to this prediction, in many experiments the peak was not eliminated by partialization using the arterial pulse. Moreover, partialization often nonuniformly reduced the peaks at the heart rate frequency in the coherence functions for different nerve pairs. These results are consistent with a model of multiple routes over which baroreceptor influences are distributed to the central c...
American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 2000
We used blockade of excitatory amino acid (EAA) neurotransmission in the medullary lateral tegmen... more We used blockade of excitatory amino acid (EAA) neurotransmission in the medullary lateral tegmental field (LTF) and rostral ventrolateral medulla (RVLM) to assess the roles of these regions in the control of inferior cardiac sympathetic nerve discharge (SND) and mean arterial pressure (MAP) in urethan-anesthetized, baroreceptor-denervated cats. Bilateral microinjection of a non- N-methyl-d-aspartate (NMDA)-receptor antagonist [1,2,3,4-tetrahydro-6-nitro-2,3-dioxobenzo-[f]quinoxaline-7-sulfonamide (NBQX)] into the LTF significantly decreased SND to 46 ± 4% of control (as demonstrated with power-density spectral analysis) and MAP by 16 ± 6 mmHg. In contrast, bilateral microinjection of an NMDA-receptor antagonist [d(−)-2-amino-5-phosphonopentanoic acid (d-AP5)] into the LTF did not decrease SND or MAP. These results demonstrate that the LTF is an important synaptic relay in the pathway responsible for basal SND in the cat. Bilateral microinjection of NBQX or d-AP5 into the RVLM signi...
Turkish Journal of Biochemistry, 2018
Turkiye Klinikleri Journal of Case Reports, 1990