Cannabinoid receptor activation in the nucleus tractus solitaries produces baroreflex-like responses in the rat

Murat S. Durakoglugil, Hakan S. Orer

Research output: Contribution to journalArticle

3 Scopus citations

Abstract

The effects of cannabinoids on the baroreflex have been investigated in the nucleus tractus solitarii (NTS). In urethane-anesthetized rats, microinjection of the cannabinoid (CB) receptor agonist WIN 55212-2 (100 mM) into the NTS produced a short lasting decrease in arterial pressure (from 95.2 ± 2.9 to 76.2 ± 1.5, n=5, P<0.05) but no change in the heart rate. Another cannabinoid agonist, CP 55940 (100 mM) also caused hypotensive responses (from 90.2 ± 11.3 to 66.4 ± 12.3 mmHg, n=5, P<0.05). Simultaneous sympathetic nerve discharge recordings showed suppression prior to the arterial pressure lowering effect of these agonists. Microinjection of the cannabinoid receptor antagonist, AM 281 (70 mM) did not cause any significant change in arterial pressure (from 100.8 ± 12 mmHg to 108.1 ± 12.8 mmHg, n=5, P>0.05) though it inhibited the agonist-induced responses. The non-NMDA receptor antagonist, DNQX (4 mM) microinjections antagonized the actions of CB agonist WIN 55212-2. Furthermore, sinoaortic denervation attenuated the responses to CB agonists suggesting an intact baroreflex arc is necessary to elicit CB-mediated effects. Neither WIN 55212-2 nor AM 281, altered baroreceptor reflex activation by bolus phenylephrine (25 microg//kg) injections. These data suggest that cannabinoid receptors in the NTS are not involved in the tonic regulation of the arterial pressure but may have a modulatory role in the baroreceptor reflex integration.

Original languageEnglish (US)
Pages (from-to)229-237
Number of pages9
JournalInternational Journal of Biomedical Science
Volume4
Issue number3
Publication statusPublished - Sep 15 2008

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Keywords

  • Arterial pressure
  • Brain stem
  • Cannabinoids
  • Cardiovascular integration
  • Glutamate

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Medicine(all)

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