[Effects of peripheral electric stimulation on the central 5-hydroxytryptamine in mice: relation to the peripheral stimulation-produced analgesia (author's transl)].
Effects of peripheral electric stimulation (PES) on the functional state of central 5-hydroxytryptamine (5-HT) and on the analgesic effect were investigated in mice. The PES was administered by a passing rectangular wave (0.45 mA, 5 msec, 5-100 Hz) for 2 hr through bipolar electrodes implanted subcutaneously at the base of the tail. Whole brain 5-HT concentration remained unchanged with the PES at 20 Hz, whereas 5-hydroxy-indoleacetic acid concentrations were significantly increased in the whole brain. A significant increase in the whole brain compared with that in control was already attained at 30 min after initiation of the PES. Number of head-twitches induced by 5-methoxy-N,N-dimethyltryptamine after the PES was clearly potentiated. Increase in the number of head-twitches after the PES was abolished by administration of p-chlorophenylalanine, a 5-HT depletor, and 5,6-dihydroxytryptamine, a 5-HT neurotoxin. The PES for 1 hr produced an antinociceptive effect. Administration of L-5-hydroxytryptophan enhanced the antinociceptive effect induced by PES, while methysergide and naloxone completely abolished this antinociception. Thus, 5-HT neurons are probably excited functionally by the PES, and the mechanisms of analgesia produced by the PES involve both endogenous opiate systems and central serotonergic mechanisms.
D006916:5-Hydroxytryptophan / Q000494:pharmacology; D000698:Analgesia; D000818:Animals; D001923:Brain Chemistry / Q000187:drug effects; D003345:Corticosterone / Q000097:blood; D004558:Electric Stimulation; D008297:Male; D008732:Methoxydimethyltryptamines / Q000494:pharmacology; D008784:Methysergide / Q000494:pharmacology; D051379:Mice; D009020:Morphine / Q000494:pharmacology; D009270:Naloxone / Q000494:pharmacology; D012701:Serotonin / Q000378:metabolism*; D013997:Time Factors
D008732:Methoxydimethyltryptamines; D012701:Serotonin; D009270:Naloxone; D009020:Morphine; D006916:5-Hydroxytryptophan; D003345:Corticosterone; D008784:Methysergide