OPIATE-LIKE EXCITATORY EFFECTS OF STEROID SULFATES AND CALCIUM-COMPLEXING AGENTS GIVEN CEREBRO-VENTRICULARLY

Intracerebroventricular administration of 10-20 μg of steroid-O-sulfates induced hypermotility, agitation, salivation, EEG abnormalities, stereotypies, wet dog shakes and seizures. Equivalent effects resulted from 30-200 μg morphine sulfate (H2SO4 salt), 50 μg EGTA or 300-400 μg of sodium sulfate or phosphate, but not chloride, nitrate or acetate. Non-steroid sulfates, steroid glucuronides and steroid phosphates were inactive. Naloxone, previously found to antagonize the excitatory effects of androsterone sulfate, failed to antagonize those of cortisol sulfate, sodium sulfate or EGTA. These findings suggest a role for extracellular calcium ions and for sulfate derived from circulating steroids in central responses to opiates. © 1979.