Effect of Age on the Prejunctional Alpha-adrenoceptor-mediated Feedback in the Heart of Spontaneously Hypertensive Rats and Normotensive Wistar Kyoto Rats. Evidence for a Physiological Role of Prejunctional Alpha 2-adrenoceptors

Overview

Journal Naunyn Schmiedebergs Arch Pharmacol

Specialty Pharmacology

Date 1983 Jun 1

PMID 6308479

Authors

A de Jonge

P N Santing

P B Timmermans

P A van Zwieten

Affiliations

Soon will be listed here.

Abstract

The prejunctional alpha 2-adrenoceptor-mediated feedback in the heart of pithed young and adult spontaneously hypertensive rats (SHR) and corresponding normotensive Wistar Kyoto rats (WKY) was studied. After electrical stimulation of the sympathetic outflow from the spinal cord to the heart, B-HT 920 induced an inhibition of the cardiac response, which was significant at stimulation frequencies up to 1 Hz in young SHR and WKY and up to 2 Hz in the adult animals. Rauwolscine produced a potentiation of the cardiac response to electrical stimulation in SHR, which was significant from 0.2-10 Hz in young SHR and from 0.1-10 Hz in adult SHR. In young WKY, rauwolscine did not potentiate the increase in heart rate to sympathetic nerve stimulation, whereas in adult WKY alpha 2-adrenoceptor blockade by rauwolscine significantly potentiated the cardiac response to electrical stimulation at frequencies in the range of 0.2-10 Hz. In SHR the potentiation of the cardiac response to sympathetic nerve stimulation by rauwolscine was much stronger than in WKY. These results suggest that in adult animals the prejunctional alpha 2-adrenoceptor mediated feedback is more developed than in young rats. In contrast with young WKY, a significant endogenous feedback can be demonstrated in adult WKY. In SHR, however, the physiological role of prejunctional alpha 2-adrenoceptors is much more important.

References

McCulloch M, Rand M, Story D, Sutton I . Prejunctional alpha-adrenoreceptors subserve a physiological role in cardiac noradrenergic transmission. J Auton Pharmacol. 1981; 1(5):407-12. DOI: 10.1111/j.1474-8673.1981.tb00080.x. View

Weitzell R, Tanaka T, Starke K . Pre- and postsynaptic effects of yohimbine stereoisomers on noradrenergic transmission in the pulmonary artery of the rabbit. Naunyn Schmiedebergs Arch Pharmacol. 1979; 308(2):127-36. DOI: 10.1007/BF00499054. View

Langer S . Presence and physiological role of presynaptic inhibitory alpha 2-adrenoreceptors in guinea pig atria. Nature. 1981; 294(5842):671-2. DOI: 10.1038/294671a0. View

Docherty J, McGrath J . An analysis of some factors influencing alpha-adrenoceptor feed-back at the sympathetic junction in the rat heart. Br J Pharmacol. 1979; 66(1):55-63. PMC: 2043807. DOI: 10.1111/j.1476-5381.1979.tb16097.x. View

KOBINGER W, Pichler L . Investigation into different types of post- and presynaptic alpha-adrenoceptors at cardiovascular sites in rats. Eur J Pharmacol. 1980; 65(4):393-402. DOI: 10.1016/0014-2999(80)90343-x. View

Algate D, Waterfall J . Action of indoramin on pre- and postsynaptic alpha-adrenoceptors in pithed rats. J Pharm Pharmacol. 1978; 30(10):651-2. DOI: 10.1111/j.2042-7158.1978.tb13351.x. View

Kalsner S . Single pulse stimulation of guinea-pig vas deferens and the presynaptic receptor hypothesis. Br J Pharmacol. 1979; 66(2):343-9. PMC: 2043637. DOI: 10.1111/j.1476-5381.1979.tb13686.x. View

Langer S, Adler-Graschinsky E, Giorgi O . Physiological significance of alpha-adrenoceptor-mediated negative feedback mechanism regulating noradrenaline release during nerve stimulation. Nature. 1977; 265(5595):648-50. DOI: 10.1038/265648a0. View

Starke K . Presynaptic receptors. Annu Rev Pharmacol Toxicol. 1981; 21:7-30. DOI: 10.1146/annurev.pa.21.040181.000255. View

10.

Starke K, Montel H, Wagner J . Effect of phentolamine on noradrenaline uptake and release. Naunyn Schmiedebergs Arch Pharmakol. 1971; 271(2):181-92. DOI: 10.1007/BF00998579. View

11.

Drew G . Presynaptic modulation of heart rate responses to cardiac nerve stimulation in pithed rats. J Cardiovasc Pharmacol. 1980; 2(6):843-56. DOI: 10.1097/00005344-198011000-00013. View

12.

Doxey J . Effect of clonidine on cardiac acceleration in pithed rats. J Pharm Pharmacol. 1977; 29(3):173-4. DOI: 10.1111/j.2042-7158.1977.tb11277.x. View

13.

Starke K, Endo T, Taube H . Relative pre- and postsynaptic potencies of alpha-adrenoceptor agonists in the rabbit pulmonary artery. Naunyn Schmiedebergs Arch Pharmacol. 1975; 291(1):55-78. DOI: 10.1007/BF00510821. View

14.

Starke K . Regulation of noradrenaline release by presynaptic receptor systems. Rev Physiol Biochem Pharmacol. 1977; 77:1-124. DOI: 10.1007/BFb0050157. View

15.

Westfall T . Local regulation of adrenergic neurotransmission. Physiol Rev. 1977; 57(4):659-728. DOI: 10.1152/physrev.1977.57.4.659. View

16.

Angus J, Korner P . Evidence against presynaptic alpha-adrenoreceptor modulation of cardiac sympathetic transmission. Nature. 1980; 286(5770):288-91. DOI: 10.1038/286288a0. View

17.

Langer S . Presynaptic regulation of catecholamine release. Biochem Pharmacol. 1974; 23(13):1793-800. DOI: 10.1016/0006-2952(74)90187-7. View

18.

Langer S . Sixth gaddum memorial lecture, National Institute for Medical Research, Mill Hill, January 1977. Presynaptic receptors and their role in the regulation of transmitter release. Br J Pharmacol. 1977; 60(4):481-97. PMC: 1667392. DOI: 10.1111/j.1476-5381.1977.tb07526.x. View

19.

Wallenstein S, Zucker C, Fleiss J . Some statistical methods useful in circulation research. Circ Res. 1980; 47(1):1-9. DOI: 10.1161/01.res.47.1.1. View

20.

van Meel J, de Jonge A, Timmermans P, van Zwieten P . Selectivity of some alpha adrenoceptor agonists for peripheral alpha-1 and alpha-2 adrenoceptors in the normotensive rat. J Pharmacol Exp Ther. 1981; 219(3):760-7. View