Angiotensin receptor blockade in the anterior hypothalamic area inhibits stress-induced pressor responses in rats

Brain Res Bull. 2001 Dec;56(6):569-74. doi: 10.1016/s0361-9230(01)00729-8.

Abstract

Central angiotensin systems are involved in expression of pressor responses induced by immobilization stress. In this study, we examined whether angiotensin receptors in the anterior hypothalamic area are involved in the pressor response during stress exposure in rats. Intracerebroventricular injections of the angiotensin AT1-receptor antagonist losartan (6.5 and 22 nmol) attenuated pressor responses to immobilization stress dose-dependently. Injections of losartan (0.065 and 0.22 nmol) into the anterior hypothalamic area also suppressed the stress-induced pressor response dose-dependently, whereas intraventricular injection of losartan (2.2 nmol) did not affect it. Immobilization stress caused increases in plasma catecholamine levels. The stress-induced increase of plasma catecholamine levels was also inhibited by angiotensin receptor blockade in the anterior hypothalamic area. The present results suggest that angiotensin receptors in the anterior hypothalamic area are involved in expression of the pressor response and sympathetic activation induced by immobilization stress.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Angiotensin Receptor Antagonists
  • Angiotensins / metabolism*
  • Animals
  • Anterior Hypothalamic Nucleus / cytology
  • Anterior Hypothalamic Nucleus / drug effects
  • Anterior Hypothalamic Nucleus / metabolism*
  • Antihypertensive Agents / pharmacology
  • Blood Pressure / drug effects
  • Blood Pressure / physiology*
  • Catecholamines / blood
  • Losartan / pharmacology
  • Male
  • Neurons / cytology
  • Neurons / drug effects
  • Neurons / metabolism*
  • Rats
  • Rats, Wistar
  • Receptors, Angiotensin / metabolism*
  • Restraint, Physical / adverse effects
  • Stress, Physiological / metabolism*
  • Stress, Physiological / physiopathology

Substances

  • Angiotensin Receptor Antagonists
  • Angiotensins
  • Antihypertensive Agents
  • Catecholamines
  • Receptors, Angiotensin
  • Losartan