P. Beaulieu - Academia.edu (original) (raw)

Papers by P. Beaulieu

Research paper thumbnail of Involvement of cannabinoid receptors in peripheral and spinal morphine analgesia

Neuroscience, 2014

The interactions between the cannabinoid and opioid systems for pain modulation are reciprocal. H... more The interactions between the cannabinoid and opioid systems for pain modulation are reciprocal. However, the role and the importance of the cannabinoid system in the antinociceptive effects of opioids remain uncertain. We studied these interactions with the goal of highlighting the involvement of the cannabinoid system in morphineinduced analgesia. In both phases of the formalin test, intra paw and intrathecal morphine produced similar antinociceptive effects in C57BL/6, cannabinoid type 1 and type 2 receptor wild-type (respectively cnr1WT and cnr2WT) mice. In cnr1 and cnr2 knockout (KO) mice, at the dose used the antinociceptive effect of intra paw morphine in the inflammatory phase of the formalin test was decreased by 87% and 76%, respectively. Similarly, the antinociceptive effect of 0.1 lg spinal morphine in the inflammatory phase was abolished in cnr1KO mice and decreased by 90% in cnr2KO mice. Interestingly, the antinociceptive effect of morphine in the acute phase of the formalin test was only reduced in cnr1KO mice. Notably, systemic morphine administration produced similar analgesia in all genotypes, in both the formalin and the hot water immersion tail-flick tests. Because the pattern of expression of the mu opioid receptor (MOP), its binding properties and its G protein coupling remained unchanged across genotypes, it is unlikely that the loss of morphine analgesia in the cnr1KO and cnr2KO mice is the consequence of MOP malfunction or downregulation due to the absence of its heterodimerization with either the CB 1 or the CB 2 receptors, at least at the level of the spinal cord. Ó

Research paper thumbnail of Phonomyography of the corrugator supercilii muscle: signal characteristics and best recording site

European Journal of Anaesthesiology, 2001

Research paper thumbnail of Inhibition of acetaminophen analgesic action by ondansetron after amygdalectomy in children: the Paratron randomized trial

European Journal of Anaesthesiology, 2013

Research paper thumbnail of Peptidic regulation of heart rate and interactions with the autonomic nervous system

Cardiovascular Research, 1998

Autonomic influences on the heart rate have been the subject of intense research for many decades... more Autonomic influences on the heart rate have been the subject of intense research for many decades and are classically devoted to the sympathetic and parasympathetic systems. However, developments over the past few years in our knowledge of the organization of the autonomic nervous system have led to the conclusion that in addition to the classical transmitters, peptidic transmitters are clearly present and have direct or indirect actions on cardiac conduction. Neuropeptides have been found to collocate with each other or with classical transmitters, thereby increasing the variety of chemical signals that a neuron can utilize to communicate with other cells. Neuropeptides can act as neurotransmitters, neuromodulators or neurohormones. Some are produced in endocrine glands and circulate as hormones, while others are contained in cardiac myocytes, neurons, or endothelial cells in proximity to the sinoatrial node and can therefore act in a paracrine or autocrine way on the pacemaker cells to modulate heart frequency. There is evidence supporting such a role, especially for locally situated neuropeptide Y, vasoactive intestinal peptide, calcitonin gene-related peptide, substance P, angiotensin II, natriuretic peptides, endothelins and possibly many others. The role of the peptidic neurotransmitters in the conduction system should not be exaggerated. Nevertheless, neuropeptides certainly represent a new category of neurotransmitters forming a third component of the autonomic nervous system and may have complex actions with potential therapeutic implications in man. q 1998 Elsevier Science B.V.

Research paper thumbnail of The antinociceptive effects of intraplantar injections of 2-arachidonoyl glycerol are mediated by cannabinoid CB 2 receptors

British Journal of Pharmacology, 2007

Research paper thumbnail of Inhibition de l’action antalgique du paracétamol par l’ondansétron après une amygdalectomie chez les enfants : une étude randomisée Paratron

Annales Françaises d'Anesthésie et de Réanimation, 2013

Research paper thumbnail of The Pharmacodynamics of Ropivacaine and Bupivacaine in Combined Sciatic and Femoral Nerve Blocks for Total Knee Arthroplasty

Anesthesia & Analgesia, 2006

The potency of ropivacaine compared with bupivacaine in regional anesthesia remains controversial... more The potency of ropivacaine compared with bupivacaine in regional anesthesia remains controversial. Therefore, we compared the pharmacodynamics of equal concentrations of bupivacaine and ropivacaine in combined sciatic and femoral nerve blocks for patients undergoing knee arthroplasty. Fifty patients received 40 mL of either 0.5% bupivacaine (n ϭ 25) or 0.5% ropivacaine (n ϭ 25) divided between the sciatic (15 mL) and the femoral (25 mL) nerves before induction of anesthesia. Loss and recovery of sensory (% of cold sensation compared to opposite side) and motor (no contraction or normal muscle force) functions were recorded in the distribution of the femoral, saphenous, common peroneal, and tibial nerves. Pain scores and morphine consumption over 48 h were also evaluated. There were no difference between bupivacaine and ropivacaine in terms of onset of sensory and motor blockade. However, resolution of sensory and motor function was faster in the ropivacaine group but only significantly so for the sciatic nerve and between 24 to 28 h for sensory resolution and 12 to 20 h for motor function. Overall, pain scores and morphine consumption were similar. In conclusion, we showed that block resolution is different between bupivacaine and ropivacaine when administered for combined sciatic and femoral nerve blocks. A new systematic method to assess sciatic and femoral nerve blockade is proposed.

Research paper thumbnail of Aparatos de anestesia

EMC - Anestesia-Reanimación, 2013

ABSTRACT

Research paper thumbnail of Involvement of cannabinoid receptors in peripheral and spinal morphine analgesia

Neuroscience, 2014

The interactions between the cannabinoid and opioid systems for pain modulation are reciprocal. H... more The interactions between the cannabinoid and opioid systems for pain modulation are reciprocal. However, the role and the importance of the cannabinoid system in the antinociceptive effects of opioids remain uncertain. We studied these interactions with the goal of highlighting the involvement of the cannabinoid system in morphineinduced analgesia. In both phases of the formalin test, intra paw and intrathecal morphine produced similar antinociceptive effects in C57BL/6, cannabinoid type 1 and type 2 receptor wild-type (respectively cnr1WT and cnr2WT) mice. In cnr1 and cnr2 knockout (KO) mice, at the dose used the antinociceptive effect of intra paw morphine in the inflammatory phase of the formalin test was decreased by 87% and 76%, respectively. Similarly, the antinociceptive effect of 0.1 lg spinal morphine in the inflammatory phase was abolished in cnr1KO mice and decreased by 90% in cnr2KO mice. Interestingly, the antinociceptive effect of morphine in the acute phase of the formalin test was only reduced in cnr1KO mice. Notably, systemic morphine administration produced similar analgesia in all genotypes, in both the formalin and the hot water immersion tail-flick tests. Because the pattern of expression of the mu opioid receptor (MOP), its binding properties and its G protein coupling remained unchanged across genotypes, it is unlikely that the loss of morphine analgesia in the cnr1KO and cnr2KO mice is the consequence of MOP malfunction or downregulation due to the absence of its heterodimerization with either the CB 1 or the CB 2 receptors, at least at the level of the spinal cord. Ó

Research paper thumbnail of Phonomyography of the corrugator supercilii muscle: signal characteristics and best recording site

European Journal of Anaesthesiology, 2001

Research paper thumbnail of Inhibition of acetaminophen analgesic action by ondansetron after amygdalectomy in children: the Paratron randomized trial

European Journal of Anaesthesiology, 2013

Research paper thumbnail of Peptidic regulation of heart rate and interactions with the autonomic nervous system

Cardiovascular Research, 1998

Autonomic influences on the heart rate have been the subject of intense research for many decades... more Autonomic influences on the heart rate have been the subject of intense research for many decades and are classically devoted to the sympathetic and parasympathetic systems. However, developments over the past few years in our knowledge of the organization of the autonomic nervous system have led to the conclusion that in addition to the classical transmitters, peptidic transmitters are clearly present and have direct or indirect actions on cardiac conduction. Neuropeptides have been found to collocate with each other or with classical transmitters, thereby increasing the variety of chemical signals that a neuron can utilize to communicate with other cells. Neuropeptides can act as neurotransmitters, neuromodulators or neurohormones. Some are produced in endocrine glands and circulate as hormones, while others are contained in cardiac myocytes, neurons, or endothelial cells in proximity to the sinoatrial node and can therefore act in a paracrine or autocrine way on the pacemaker cells to modulate heart frequency. There is evidence supporting such a role, especially for locally situated neuropeptide Y, vasoactive intestinal peptide, calcitonin gene-related peptide, substance P, angiotensin II, natriuretic peptides, endothelins and possibly many others. The role of the peptidic neurotransmitters in the conduction system should not be exaggerated. Nevertheless, neuropeptides certainly represent a new category of neurotransmitters forming a third component of the autonomic nervous system and may have complex actions with potential therapeutic implications in man. q 1998 Elsevier Science B.V.

Research paper thumbnail of The antinociceptive effects of intraplantar injections of 2-arachidonoyl glycerol are mediated by cannabinoid CB 2 receptors

British Journal of Pharmacology, 2007

Research paper thumbnail of Inhibition de l’action antalgique du paracétamol par l’ondansétron après une amygdalectomie chez les enfants : une étude randomisée Paratron

Annales Françaises d'Anesthésie et de Réanimation, 2013

Research paper thumbnail of The Pharmacodynamics of Ropivacaine and Bupivacaine in Combined Sciatic and Femoral Nerve Blocks for Total Knee Arthroplasty

Anesthesia & Analgesia, 2006

The potency of ropivacaine compared with bupivacaine in regional anesthesia remains controversial... more The potency of ropivacaine compared with bupivacaine in regional anesthesia remains controversial. Therefore, we compared the pharmacodynamics of equal concentrations of bupivacaine and ropivacaine in combined sciatic and femoral nerve blocks for patients undergoing knee arthroplasty. Fifty patients received 40 mL of either 0.5% bupivacaine (n ϭ 25) or 0.5% ropivacaine (n ϭ 25) divided between the sciatic (15 mL) and the femoral (25 mL) nerves before induction of anesthesia. Loss and recovery of sensory (% of cold sensation compared to opposite side) and motor (no contraction or normal muscle force) functions were recorded in the distribution of the femoral, saphenous, common peroneal, and tibial nerves. Pain scores and morphine consumption over 48 h were also evaluated. There were no difference between bupivacaine and ropivacaine in terms of onset of sensory and motor blockade. However, resolution of sensory and motor function was faster in the ropivacaine group but only significantly so for the sciatic nerve and between 24 to 28 h for sensory resolution and 12 to 20 h for motor function. Overall, pain scores and morphine consumption were similar. In conclusion, we showed that block resolution is different between bupivacaine and ropivacaine when administered for combined sciatic and femoral nerve blocks. A new systematic method to assess sciatic and femoral nerve blockade is proposed.

Research paper thumbnail of Aparatos de anestesia

EMC - Anestesia-Reanimación, 2013

ABSTRACT