Abstract
.gamma.-Hydroxybutyric acid [an anesthetic and sedative agent, GHBA] increased arterial blood pressure and heart rate dose-dependently following i.p. and intracerebroventricular administration to conscious rats. Cardiovascular responses to GHBA were completely prevented after pretreatment with reserpine or phenoxybenzamine and after a prehypothalamic brain transection. GHBA increased brain noradrenaline [norepinephrine, NA] synthesis and utilization, particularly in the neocortex. Selective central NA depletion in combination with NA synthesis inhibition prevented the cardiovascular effects of GHBA. No overt interactions were observed with agents influencing 5-hydroxytryptamine (5-HT), dopamine (DA) or acetylcholine (Ach) transmission. Pentobarbitone but not diazepam or diphenylhydantoin abolished the hypertensive properties of GHBA. The cardiovascular effects of GHBA are of central origin and they are mediated via the peripheral sympathetic nervous system. They are dependent on an intact central NA transmission while there are few indications for a significant role of central DA-, 5-HT or Ach-mechanisms.