Blockade of non-NMDA receptors attenuates reflex pressor response to static contraction

J. M. Hill, J. G. Pickar, Marc P Kaufman

Research output: Contribution to journalArticle

18 Scopus citations

Abstract

Considerable evidence suggests that both substance P and glutamate play a role in the spinal transmission of the exercise pressor reflex. We tested two hypotheses. First, after a lumbosacral intrathecal injection of a glutamatergic receptor antagonist, the reflex cardiovascular and ventilatory responses to static contraction are attenuated. Second, after a lumbosacral intrathecal injection of a substance P receptor antagonist and a glutamatergic receptor antagonist, the reflex cardiovascular and ventilatory responses to static contraction are abolished. We found that 1) the reflex cardiovascular responses to static contraction were unaffected (P > 0.05) after the intrathecal injection of the N-methyl-D-aspartate (NMDA) receptor antagonists, dl-2-amino-5-phosphonopentanoate (±AP-5) or 3-[(±)-2- carboxypiperazin-4-yl]propyl-1-phosphonic acid (±CPP); 2) the reflex pressor response to static muscular contraction was attenuated by >50% after the intrathecal injection of the non-NMDA receptor antagonist, 6-cyano-7- nitroquinoxaline-2,3-dione (CNQX); and 3) the reflex pressor response to static contraction was almost abolished after the intrathecal injection of the substance P receptor antagonist, CP-96,345, and CNQX. Our results suggest that substance P and glutamate are two neurotransmitters involved in the spinal transmission of the exercise pressor reflex and that substance P and glutamate exert their effects via neurokinin-1 (NK-1) and non-NMDA receptors, respectively.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume266
Issue number5 35-5
StatePublished - 1994

Keywords

  • autonomic nervous system
  • cats
  • CP-96,345
  • exercise
  • groups III and IV muscle afferents
  • spinal cord

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Physiology

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