Mohammed H. ABDULLA, - *, Munavvar A. SATTAR, Nor A. ABDULLAH

The interaction between renin-angiotensin system and sympathetic nervous system in the peripheral vasculature of normal Sprague-Dawley rats

To evaluate possible interactions between the renin-angiotensin system (RAS) and the sympathetic nervous system (SNS) in the systemic circulation upon the intravenous administration of angiotensin II and a set of adrenergic agonists in normal Sprague-Dawley (SD) rats. Rats were treated with carvedilol, a non-selective b- and selective a1-adrenoceptor blocker, in a dose of (5 mg/kg) orally for 7 days, and on day 8, the animals were pentobarbitone-anaesthetized and prepared for systemic hemodynamic study. Dose-response relationships in terms of elevation in the magnitude of the mean arterial blood pressure in response to intravenous injection of noradrenaline (NA), phenylephrine (PE), methoxamine (ME), and angiotensin II (Ang II) were determined. Data, mean ± S.E.M., were subjected to ANOVA with significance at P < 0.05. Carvedilol blunted the peripheral vascular response to NA, PE, ME, and Ang II (all P < 0.05). It is concluded that peripheral vasoconstriction induced by Ang II is contributed to by adrenergic action. Furthermore, there is a cross-talk relationship between RAS and SNS in determining the responsiveness of the peripheral vasculature to adrenergic agonists and angiotensin II in normal rats.

Anahtar Kelimeler:

Key words: Carvedilol, methoxamine, angiotensin II, Sprague-Dawley rats

The interaction between renin-angiotensin system and sympathetic nervous system in the peripheral vasculature of normal Sprague-Dawley rats

Keywords:

Key words: Carvedilol, methoxamine, angiotensin II, Sprague-Dawley rats,

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Reid IA. Interactions between ANG II, sympathetic nervous system, and baroreceptor refl exes in regulation of blood pressure. Am J Physiol 262: E763-E778, 1992. 2. De Jonge AJ, Th oolen MJMC, Timmermans PBMWM et al. Interaction of converting enzyme inhibition of converting enzyme inhibitors with the sympathetic nervous system. Progr Pharmacol 5: 25-38, 1984.
Grassi G. Renin-angiotensin-sympathetic crosstalks in hypertension: reappraising the relevance of peripheral interactions. J Hypertens 19: 1713-1716, 2001.
Sealey JE, Laragh JH. Th e renin-angiotensin-aldosterone system for neural regulation of blood pressure and sodium and potassium homeostasis. In: Laragh JG, Brenner BM. eds.. Hypertension: pathophysiology, diagnosis and management. Raven Press; 1995: pp. 1763-1795.
Shepherd JT, Mancia G. Refl ex control of the human cardiovascular system. Rev Physiol Biochem Pharmacol 105: 1-99, 1986. 6. Squire IB, Reid JL. Interactions between the renin-angiotensin system and autonomic nervous system. In: Th e renin- angiotensin system, Vol. 37. (Eds JIS Robert & MG Nicholis). Gower Medical Publishing; 1993: pp. 1-16.
Rodríguez-Pérez JC, Cabrera JJ, Anabitarte A et al. Eff ects of carvedilol in rats with induced chronic kidney failure. Nefrologia 21: 52-58, 2001.
Rodríguez-Pérez JC, Losada A, Anabitarte A et al. Eff ects of the novel multiple-action agent carvedilol on severe nephrosclerosis in renal ablated rats. J Pharmacol Exp Th er 283: 336-404, 1997.
Jarajapu YPR, Hillier C, MacDonald A. Th e α1A-adrenoceptor subtypes mediate contraction in rat femoral resistance arteries. Eur J Pharmacol 422: 127-135, 2001.
Zacharia J, Hillar C, MacDonald A. α1-adrenoceptor subtypes involved in vasoconstrictor responses to exogenous and neurally released in rat femoral resistance arteries. Br J Pharmacol 141: 915-924, 2004.
Khan MA, Sattar MA, Abdullah NA et al. Alpha1B- adrenoceptors mediate adrenergically-induced renal vasoconstrictions in rats with renal impairment. Acta Pharmacol Sin 29: 193-203, 2008.
Armenia A, Munavvar AS, Abdullah NA et al. Th e contribution of adrenoceptor subtype(s) in the renal vasculature of diabetic spontaneously hypertensive rats. Br J Pharmacol 142: 719-26, 2004.
Tsujimoto G, Tsujimoto A, Suzuki E et al. Glycogen phosphorylase activation by two diff erent α1 adrenergic receptor subtypes: Methoxamine selectively stimulates a putative α1 adrenergic receptor subtype (α1A) that couples with Ca++ infl ux. J Pharmacol Exp Th er 36: 166-176, 1989.
Arévalo-León LE, Gallardo-Ortyz IA, Urquiza-Maryn H et al. Evidence for the role of α1D and α1A adrenoceptors in contraction of rat mesenteric artery. Vascul Pharmacol 40: 91- 96, 2003.
De Jonge A, Knape J, van Meel J et al. Eff ect of converting enzyme inhibition and angiotensin receptor blockade on the vasoconstriction mediated by alpha 1- and alpha 2-adrenoceptor stimulation in pithed normotensive rats. Naunyn Schmiedebergs Arch Pharmacol 321: 309-313, 1982.
Chen K, Zimmerman G. Angiotensin II-mediated renal vasoconstriction amenable to α1-adrenoceptor blockade. Eur J Pharmacol 284: 281-288, 1995.
Batenburg WW, Van Esch JHM, Garrelds IM et al. Carvedilol- induced antagonism of angiotensin II: a matter of [alpha]1- adrenoceptor blockade. Hypertension 24: 1355-1363, 2006.
Rathore HA, Munavvar AS, Abdullah NA et al. Interaction between renin-angiotensin and sympathetic nervous systems in a rat model of pressure overload cardiac hypertrophy. Auton Autacoid Pharmacol 29: 171-180, 2009.