Single-unit responses of serotonergic neurons to vasoactive drug administration in behaving cats

C. A. Fornal, W. J. Litto, D. A. Morilak, B. L. Jacobs

Research output: Contribution to journalArticle

15 Scopus citations

Abstract

Single-unit activity of serotonergic neurons in the dorsal raphe nucleus (DRN), heart rate (HR), and arterial blood pressure were recorded in freely moving cats during spontaneous behavior and in response to systemic administration of vasoactive drugs. The activity of serotonergic neurons varied in association with behavioral arousal but was unrelated to spontaneous fluctuations in HR and blood pressure. Bolus administration of phenylephrine hydrochloride and sodium nitroprusside (15-20 μg/kg iv) produced a rapid transient increase (35 mmHg) and decrease (49 mmHg), respectively, in mean arterial pressure (MAP). Infusion of phenylephrine and sodium nitroprusside (100 μg/ml) produced sustained hypertension (avg MAP 166 mmHg) and hypotension (avg MAP 49 mmHg), respectively. The activity of serotonergic neurons was not significantly altered in response to phenylephrine or sodium nitroprusside administration. Furthermore, no significant changes in unit activity were observed after hydralazine administration (1 mg/kg iv) despite prolonged reflex activation of sympathetic outflow. Thus the activity of DRN serotonergic neurons was unrelated to transient alterations in blood pressure and baroreceptor activity. These results suggest that changes in the activity of serotonergic DRN neurons are not involved in physiological mechanisms underlying reflex alterations in sympathetic (and parasympathetic) outflow invoked by hypertension and hypotension.

Original languageEnglish (US)
Pages (from-to)R963-R972
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume259
Issue number5 28-5
DOIs
StatePublished - 1990

All Science Journal Classification (ASJC) codes

  • Physiology
  • Physiology (medical)

Keywords

  • 8-Hydroxy-2-(di-n-propylamino)tetralin
  • Blood pressure
  • Cardiovascular regulation
  • Dorsal raphe nucleus
  • Hydralazine
  • Phenylephrine hydrochloride
  • Sleep-wake cycle
  • Sodium nitroprusside
  • Sympathetic activity

Fingerprint Dive into the research topics of 'Single-unit responses of serotonergic neurons to vasoactive drug administration in behaving cats'. Together they form a unique fingerprint.

  • Cite this