Role of V 1 receptors in the action of vasopressin on the baroreflex control of heart rate

John Luk, I. Ajaelo, V. Wong, J. Wong, D. Chang, L. Chou, I. A. Reid

Research output: Contribution to journalArticle

49 Citations (Scopus)

Abstract

Arginine vasopressin (AVP) elicits a larger decrease in heart rate for a given increase in arterial pressure than do other vasoconstrictors, but there is disagreement as to whether this results from an increase in baroreflex gain or a resetting of the baroreflex to a lower blood pressure. It is also unclear which type of vasopressin receptor mediates the action of vasopressin on the baroreflex. In the present study, the effects of vasopressin, selective vasopressin V 1 and V 2 receptor agonists, oxytocin, and a vasopressin V 1 receptor antagonist on the baroreflex control of heart rate were investigated in conscious, chronically prepared rabbits. Baroreflex curves were generated with intravenous infusions of phenylephrine and nitroprusside and analyzed using a four-parameter logistic model. Intravenous infusion of vasopressin at 5 ng · kg -1 · min -1 increased mean arterial pressure by 9 mmHg and decreased heart rate by 31 beats/min. The arterial pressure at the midrange of the baroreflex curve (BP 50 ) decreased from 75.9 ± 4.8 to 57.6 ± 1.7 mmHg (P < 0.01), indicating a shift of the baroreflex curve to a lower pressure, but the gain did not change significantly. The actions of vasopressin on blood pressure, heart rate, and BP 50 were completely blocked by pretreatment with d(CH 2 ) 5 [Tyr(Me) 2 ]AVP, a selective V 1 receptor antagonist. Infusion of [Phe 2 ,Ile 3 ,Orn 8 ]AVP, a selective V 1 receptor agonist, produced cardiovascular effects similar to those of vasopressin and decreased the BP 50 of the baroreflex from 73.0 ± 2.2 to 63.8 ± 2.2 mmHg (P < 0.05). Neither deamino-[D-Arg 8 ]AVP (DDAVP), a selective V 2 receptor agonist, nor oxytocin significantly altered blood pressure and heart rate or the BP 50 of the baroreflex. These results provide evidence that infusion of vasopressin in conscious rabbits resets the baroreflex control of heart rate to a lower pressure without increasing its gain and demonstrate that this action is mediated by vasopressin V 1 receptors.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume265
Issue number3 34-3
StatePublished - Jan 1 1993

Fingerprint

Baroreflex
Vasopressins
Heart Rate
Arginine Vasopressin
Vasopressin Receptors
Arterial Pressure
Blood Pressure
Intravenous Infusions
Oxytocin Receptors
Rabbits
Pressure
Nitroprusside
Phenylephrine
Vasoconstrictor Agents
Oxytocin
Logistic Models

Keywords

  • V receptors
  • baroreflex resetting
  • blood pressure
  • oxytocin
  • rabbit
  • vasopressin antagonist

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

Cite this

Role of V 1 receptors in the action of vasopressin on the baroreflex control of heart rate . / Luk, John; Ajaelo, I.; Wong, V.; Wong, J.; Chang, D.; Chou, L.; Reid, I. A.

In: American Journal of Physiology - Regulatory Integrative and Comparative Physiology, Vol. 265, No. 3 34-3, 01.01.1993.

Research output: Contribution to journalArticle

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