Central effects of somatostatin: pressor response, AVP release, and sympathoinhibition.
The effects of intracerebroventricular (icv) administration of somatostatin(1-14) (SS1-14) on mean arterial blood pressure (MAP), heart rate (HR), plasma arginine vasopressin (AVP) concentration, and splanchnic nerve activity (SpNA) were studied in conscious rats. In addition, the effects of peripheral alpha-adrenergic receptor blockade with prazosin, vasopressinergic V1-receptor blockade with [d(CH2)5Tyr(Me)]AVP, and chronic bilateral sinoaortic denervation (SAD) on central SS1-14-induced MAP, HR, and SpNA responses were investigated. SS1-14 icv elicited dose-dependent increases in MAP and plasma AVP concentration as well as decreases in HR and SpNA. Prazosin iv did not significantly affect SS1-14-induced pressor and bradycardic responses but augmented the decrease in SpNA. The V1-AVP receptor antagonist iv significantly attenuated the effects of SS1-14 icv on MAP, HR, and SpNA. Following SAD the pressor responses to SS1-14 icv were significantly enhanced and were associated with significantly smaller decreases in HR and SpNA. We conclude that central administration of SS1-14 causes a pressor response via release of AVP while at the same time inhibiting peripheral sympathetic outflow. Our results support the hypothesis that SS1-14 in the brain by its effects on AVP release and sympathetic outflow may participate in central cardiovascular regulation.
Rettig
R
R
Department of Pharmacology, University of Heidelberg, Federal Republic of Germany.
Geist
R
R
Sauer
U
U
Rohmeiss
P
P
Unger
T
T
D000317:Adrenergic alpha-Antagonists / Q000502:physiology; D000818:Animals; D001127:Arginine Vasopressin / Q000378:metabolism*; D001794:Blood Pressure / Q000187:drug effects*; D001921:Brain / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D006339:Heart Rate / Q000187:drug effects; D007276:Injections, Intraventricular; D008297:Male; D009407:Nerve Block; D009433:Neural Inhibition; D051381:Rats; D011919:Rats, Inbred Strains; D011945:Receptors, Angiotensin / Q000502:physiology; D017483:Receptors, Vasopressin; D013004:Somatostatin / Q000494:pharmacology*; D013564:Sympathetic Nervous System / Q000187:drug effects*; D014667:Vasopressins
D000317:Adrenergic alpha-Antagonists; D011945:Receptors, Angiotensin; D017483:Receptors, Vasopressin; D014667:Vasopressins; D001127:Arginine Vasopressin; D013004:Somatostatin