Angiotensin II mediates catecholamine and neuropeptide Y secretion in human adrenal chromaffin cells through the AT1 receptor (original) (raw)
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Canadian Journal of Physiology and Pharmacology, 1992
VATTA, M. S., BHANCIOTTI, L. G., LWATELLI, A. S., PAPOUCHADO, M e L., and FERNANDBZ, B. E. 1992. Monophasic and biphasic effects of mgiotensin II and III on norepinephrine uptake and release in sat adrenal medulla. Can. J. Bhysiol.
High-affinity angiotensin receptors in rat adrenal medulla
Regulatory Peptides, 1985
Regulatory Peptídes, ll (t985) 237 243 Elsevier RPT 00385 23'l Summary Angiotensin II receptors have been quantitated in single rat adrenal medullas by incubation oftissue sections with r r sl-[Sarr]-AII, autoradiography with exposure to 3H-sensitive Ultrofllm, computerized densitometry and comparison with r25l-labelled standards. Rat adrenal medulla contains a single class of high affinity AII receptors with a ¡<" of0.84 + 0.02 x lOe M rand a B^.,of3259 + 502 fmol/mg protein, one of the highest densities in AII receptors found in rat tissues. These observations provide evidence for a local site ofaction of AII in the release ofadrenal medullary catecholamines. angiotensin II receptors; rat adrenal medulla; receptor autoradiography
Journal of the Korean Society of Hypertension, 2013
Background: The aim of this study was to examine whether PD 123319 (an angiotensin II type 2 [AT 2 ] receptor antagonist) can influence the release of catecholamines (CA) from the perfused model of the rat adrenal medulla. Methods: The adrenal gland was isolated by the modification of Wakade method, and perfused with normal Krebs-bicarbonate solution. The content of CA was measured using the fluorospectrophotometer. Results: During perfusion of PD 123319 (range, 5 to 50 nM) into an adrenal vein for 90 minutes the CA secretory responses evoked by acetylcholine (ACh), high K + , 1,1-dimethyl-4-phenylpiperazinium iodide (DMPP), and McN-A-343 was dose-and time-dependently inhibited. Furthermore, loading with PD 123319 for 90 minutes also markedly inhibited the CA secretory responses evoked by 4-dihydro-2,6-dimethyl-3-nitro-4-(2-trifluoro-methyl-phenyl)-pyridine-5-carboxylate (Bay-K-8644), cyclopiazonic acid, veratridine, and angiotensin II (Ang II). PD 123319 did not affect basal CA output. Simultaneous perfusion of PD 123319 and CGP 42112 perfused into an adrenal vein for 90 minutes rather more potently inhibited the CA seretory responses evoked by Ach, high K+, DMPP, Bay-K-8644, veratridine, and Ang II compared to the inhibitory effect by PD123319-treated alone. Conclusions: Taken together, these results show that PD 123319 inhibits the CA secretion evoked by both cholinergic and Ang II receptor stimulation from the perfused rat adrenal medulla. This inhibitory effect of PD 123319 seems to be exerted by blocking the influx of both Na + and Ca 2+ through their voltage-dependent channels into the rat adrenomedullary chromaffin cells as well as by reducing the Ca 2+ release from its cytoplasmic calcium store, which may be relevant to AT 2 receptor blockade. Based on these present data, it is thought that PD 123319 has different activity from previously known AT 2 antagonist activity in the perfused adrenal medulla, and that AT 2 receptors may be involved in the rat adrenomedullary CA secretion.
Neuroscience, 1997
There exist at least two distinct subtypes of angiotensin II receptors in the brain, namely the AT 1 and AT 2 subtypes. The high density of angiotensin II AT 1 receptors is present in the medulla oblongata. The AT 1 subtype of angiotensin II receptors mainly mediates central cardiovascular events. In the present study a polyclonal antibody against the angiotensin II AT 1 receptor and a monoclonal antibody against tyrosine hydroxylase were employed to evaluate the possible presence of angiotensin II AT 1 receptor-like immunoreactivity in the catecholaminergic neurons of the rat medulla oblongata by means of the double colour immunofluorescence technique. A weak, diffuse cytoplasmic angiotensin II AT 1 receptor-like immunoreactivity was observed in almost all the catecholaminergic cell bodies of the A2, C1, C2 and C3 cell groups, except those of the A1 cell group containing moderately intense, diffuse cytoplasmic angiotensin II AT 1 receptor-like immunoreactivity, occasionally found in the noradrenergic dendrites of the A1 cell group. There was a higher density of the angiotensin II AT 1 receptor-like immunoreactive profiles in the A2 cell group area than in other catecholaminergic cell group areas. In addition, the angiotensin II AT 1 receptor-like immunoreactivity was seen in non-catecholaminergic neurons.
Angiotensin stimulation of adrenal fasciculata cells
Archives of biochemistry and …, 1988
In this paper we provide evidence to show that the pathways by which adrenocorticotropic hormone (ACTH) and angiotensin II (AII) stimulate steroidogenesis in bovine fasciculata cells are only partially independent. Both hormones have the same intrinsic activity but a 500-fold higher dose of AI1 is required to achieve 50% stimulation of steroidogenesis. Whereas ACTH acts by way of CAMP, AI1 appears to operate through protein kinase C. The phorbol ester, 12-O-tetradecanoylphorbol-13 acetate (TPA), and the calcium ionophore, A23187, each stimulate steroidogenesis and, when added together, act synergistically. To test the relationship between the ACTH and AI1 pathways, we added the two hormones simultaneously and measured steroid production. When the hormones were present at submaximal concentrations, their effects were additive. At maximal doses, steroid production was 40% above that elicited by either hormone alone. In contrast to the action of AI1 in the glomerulosa cell where it inhibits ACTH-stimulated CAMP formation, AI1 causes no inhibition in the fasciculata. Cycloheximide inhibits steroidogenesis stimulated by AI1 or a mixture of TPA and A23187. Scatchard analysis of the binding of '=I-AI1 to particulates from adrenal cortical fasciculata indicates the presence of a single class of binding sites (& = 0.6 X 10e8 M). Binding is not inhibited by ACTH. Biotin-containing AI1 analogs that bind specifically to the particulates have been evaluated as potential tools for avidin-biotin affinity chromatography of the receptor. One of these, [NL-6-(biotinylamido)hexyllys1,Va15] AII, is a promising candidate for receptor isolation. 8 1988AeademicPress,Ine.
European Journal of Pharmacology, 1994
Interactions between a2-adrenoceptors and angiotensin II receptors were evaluated in the nucleus tractus solitarii of the rat by means of quantitative receptor autoradiography and cardiovascular analysis. In binding experiments using/-noradrenaline to compete for [3H]p-aminoclonidine binding sites, angiotensin II (1 nM) increased the IC50 value of l-noradrenaline by 50%. The angiotensin AT 1 receptor antagonist, DUP753 (losartan), not only blocked this action but also decreased the IC50 value of /-noradrenaline. The modulatory effect of angiotensin II was also evaluated after addition of both DUP753 and PD123319, an angiotensin AT 2 receptor antagonist, and counteraction of the reduction in the ICs0value of l-noradrenaline was observed. In saturation experiments angiotensin II increased the K D and Bma x values of [3H]p-aminoclonidine binding sites, compatible with possible uncoupling of the az-adrenoceptors. Cardiovascular analysis demonstrated that a threshold dose of angiotensin II (0.05 pmol) counteracted the vasodepressor effect produced by an EDs0 dose of/-adrenaline, l-noradrenaline or clonidine coinjected in the nucleus tractus solitarii. DUP753 fully blocked this in vivo modulation of az-adrenoceptors by angiotensin II. These findings suggest the existence of an antagonistic angiotensin AT1/a2-adrenoceptor interaction in the nucleus tractus solitarii. Therefore, it can be surmised that the activation of angiotensin II AT 1 receptors may reduce the transduction of the a2-adrenoceptors and thus the a2-mediated vasodepressor responses.
Neurochemical research, 2003
The characteristics and properties of the increase in cytosolic [Ca2+] that occurs in bovine adrenal medullary chromaffin cells on exposure to angiotensin 11 have been investigated. In fura-2 loaded cells exposure to a maximally effective concentration of angiotensin II (100 nM) caused a rapid, but transient increase in cytosolic [Ca2+] followed by a lower plateau that was sustained as long as external Ca2+ was present. In the absence of external Ca2+ only the initial brief transient was observed. In cells previously treated with thapsigargin in Ca2+-free medium to deplete the internal Ca2+ stores, angiotensin II caused no increase in cytosolic [Ca2+] when external Ca2+ was absent. Reintroduction of external Ca2+ to thapsigargin-treated, store-depleted cells caused a sustained increase in cytosolic [Ca2+] that was not further increased upon exposure to angiotensin II. Analysis of the data suggests that in bovine chromaffin cells angiotensin II causes Ca2+ entry via a pathway(s) acti...