[The participation of opioids in the antinociceptive effect induced by the stimulation of hypothalamic "pleasure zones" in 20- to 30-day-old rabbits].
The involvement of opioid peptides in the mediation of inhibitory influences of the positive reinforcement system ("reward areas") on the evoked potential (EPs) recorded in the thalamic parafascicular complex (CM-Pf) in response to the nociceptive electrodermal stimulation of the hind paw in 20-30 day rabbits has been studied. Electrical stimulation of "reward areas" identified in the preliminary behavioural experiments inhibited the EPs. The systemic injection of naloxone potentiated the antinociceptive effect of "reward areas" stimulation in 75% of cases under the incomplete inhibition of EPs (the decrease of EPs amplitude) but decreased its inhibitory effect in 87% of cases under the complete inhibition of EPs. Naloxone did not change the inhibitory effect of "reward areas" stimulation suggesting to the relationship of analgesic "reward areas" function with nonopioid mechanisms too. On the basis of the comparison of the present data and the ones obtained before it can be inferred that opioid mechanism in realization of antinociceptive influence of "reward areas" stimulation on EPs in CM-Pf is more important for 20-30 day rabbits compared with 41-60 day ones. The correlation of the phenomenon under investigation with the formation of neurotransmitter systems has been discussed.
D000375:Aging / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D004558:Electric Stimulation; D007031:Hypothalamus / Q000187:drug effects / Q000502:physiology*; D009270:Naloxone / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D018847:Opioid Peptides / Q000187:drug effects / Q000502:physiology*; D010146:Pain / Q000503:physiopathology*; D011817:Rabbits; D012054:Reinforcement, Psychology; D012201:Reward; D012653:Self Stimulation / Q000187:drug effects / Q000502:physiology; D013238:Stereotaxic Techniques; D013997:Time Factors
D009292:Narcotic Antagonists; D018847:Opioid Peptides; D009270:Naloxone
Uchastie opioidov v antinotsitseptivnom éffekte, vyzvannom stimuliatsieĭ gipotalamicheskikh "zon nagrady", u 20--30-sutochnykh krolikov.