Spinal sympathetic neurons: possible sites of opiate-withdrawal suppression by clonidine.
Morphine, methadone, meperidine, fentanyl, and clonidine rapidly depressed transmission through sympathetic preganglionic neurons in cats with the spinal cord transected. Naloxone promptly antagonized this effect of the opiates but not that of clonidine which was reversed by alpha 2-adrenergic receptor antagonists. The independent depression of preganglionic neurons by clonidine may contribute to the ability of this drug to depress the symptoms of opiate withdrawal that are characterized by sympathetic hyperactivity.
D000818:Animals; D002415:Cats; D003000:Clonidine / Q000494:pharmacology* / Q000627:therapeutic use; D005071:Evoked Potentials / Q000187:drug effects; D006801:Humans; D009294:Narcotics / Q000494:pharmacology; D011955:Receptors, Drug / Q000187:drug effects; D012018:Reflex / Q000187:drug effects; D013116:Spinal Cord / Q000166:cytology; D013329:Structure-Activity Relationship; D013375:Substance Withdrawal Syndrome / Q000188:drug therapy*; D013564:Sympathetic Nervous System / Q000187:drug effects*; D009435:Synaptic Transmission / Q000187:drug effects*
D009294:Narcotics; D011955:Receptors, Drug; D003000:Clonidine