Spinal vasopressin modulates the reflex cardiovascular response to static contraction

Charles L Stebbins, A. Ortiz-Acevedo, J. M. Hill

Research output: Contribution to journalArticle

14 Scopus citations

Abstract

Recent evidence has demonstrated that arginine vasopressin (AVP) may modulate primary afferent activity of nociceptors in the dorsal horn of the spinal cord. Because nociceptors are group III and IV afferents, spinal AVP also may modulate the activity of group III and IV afferents that cause reflex cardiovascular responses to muscle contraction. Thus, we compared the pressor (mean arterial pressure), myocardial contractile (dP/dt), and heart rate (HR) responses to electrically induced static contraction of the cat hindlimb before and after lumbar intrathecal (IT) injection (L1-L7) of AVP (n = 9), the V1 receptor antagonist d(CH2)5Tyr(Me)AVP (n = 6), the V2 receptor antagonist d(CH2)5[D-Ile2,Ile4,Ala-NH2 9]AVP (n = 6), and the V2 agonist [Val4,D]AVP (n = 8). After IT injection of AVP (0.1 or 1 nmol) the pressor and contractile responses to static contraction were attenuated by 55 and 44%, respectively. HR was unchanged. Forty-five to 60 min after AVP injection, the contraction-induced pressor and contractile responses were restored to control levels. V1 receptor blockade augmented contraction- induced increases in mean arterial pressure (36%) and dP/dt (49%) but not HR. V2 receptor blockade had no effect on the cardiovascular response to contraction, whereas selective V2 stimulation attenuated the dP/dt (-20%) and HR (-33%) responses but not the pressor response. These results suggest that AVP attenuates the reflex cardiovascular response to contraction by modulating sensory nerve transmission from contracting muscle primarily via a V1 receptor mechanism in the lumbar spinal cord.

Original languageEnglish (US)
Pages (from-to)731-738
Number of pages8
JournalJournal of Applied Physiology
Volume72
Issue number2
StatePublished - 1992

Keywords

  • cats
  • exercise pressor reflex
  • static muscle contraction
  • V and V receptor antagonists
  • V and V receptors

ASJC Scopus subject areas

  • Endocrinology
  • Physiology
  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation

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  • Cite this

    Stebbins, C. L., Ortiz-Acevedo, A., & Hill, J. M. (1992). Spinal vasopressin modulates the reflex cardiovascular response to static contraction. Journal of Applied Physiology, 72(2), 731-738.