Morphine suppression of bradycardia induced by electrical stimulation of gigantocellular reticular nucleus in the cat.
In chloralose-urethane-anesthetized cats, intravertebral injection of morphine (1,2 and 4 mg/kg) promoted a drastic suppression of the bradycardia elicited by stimulating the medullary gigantocelular reticular nucleus (GRN). The degree of blockadge of GRN-induced cardioinhibition was directly dependent upon the dose of morphine and inversely related to the reticular stimulus train intensity and pulse frequency. The possibility that the GRM may be a site of action for morphine in its production of hypotension and bradycardia was discussed.
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002415:Cats; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D008297:Male; D008526:Medulla Oblongata / Q000187:drug effects*; D009433:Neural Inhibition / Q000187:drug effects