Spinal noradrenergic neurotransmission and the analgesia induced by brief footshock.
Antinociception induced by brief footshock as well as by 5-methoxy-N,N-dimethyltryptamine was antagonized by lesions of the descending bulbospinal noradrenergic (NA) pathways by intrathecal injections of 6-hydroxydopamine. The alpha 2-adrenoceptor antagonist, yohimbine, injected intrathecally also blocked both types of nociceptive effects in the tail-flick and hot-plate tests. 5-Methoxy-N,N-dimethyltryptamine (1 mg/kg) potentiated shock-induced antinociception and this potentiation was also antagonized by decreased NA neurotransmission. These findings suggest an important role for spinal NA innervation, and possibly alpha 2-adrenoceptors in antinociception induced by brief footshock and serotonergic receptor stimulation induced analgesia in rats.
D000344:Afferent Pathways / Q000502:physiology; D000698:Analgesia; D000700:Analgesics / Q000494:pharmacology; D000818:Animals; D004597:Electroshock; D006892:Hydroxydopamines / Q000494:pharmacology; D007278:Injections, Spinal; D008297:Male; D008732:Methoxydimethyltryptamines / Q000494:pharmacology; D016627:Oxidopamine; D010146:Pain / Q000503:physiopathology*; D051381:Rats; D011919:Rats, Inbred Strains; D013116:Spinal Cord / Q000503:physiopathology*; D009435:Synaptic Transmission
D000700:Analgesics; D006892:Hydroxydopamines; D008732:Methoxydimethyltryptamines; D016627:Oxidopamine