Functional studies with the opioid peptide dynorphin: acute effects of injections into the substantia nigra reticulata of naive rats.
When injected into the substantia nigra reticulata of naive rats, dynorphin-(1-17) caused a dose dependent contralateral rotation which was inhibited by naloxone in a dose dependent manner. Met-enkephalin injected in the same coordinates as the ones used with dynorphin also induced rotation but of lower intensity, while Leu-enkephalin did not elicit any significant response at the doses tested. D-amphetamine, injected subcutaneously 60 min after dynorphin, significantly enhanced the contralateral rotation induced by the intranigral administration of dynorphin. Experiments with dynorphin injections combined with D-amphetamine suggest that the dynorphin effects are mediated by neuronal loops involving dynorphin dopamine interactions.
D000818:Animals; D003913:Dextroamphetamine / Q000494:pharmacology; D004399:Dynorphins; D004723:Endorphins / Q000494:pharmacology*; D007839:Functional Laterality; D008297:Male; D009043:Motor Activity / Q000187:drug effects*; D009270:Naloxone / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012399:Rotation; D013378:Substantia Nigra / Q000187:drug effects / Q000502:physiology*
D004723:Endorphins; D009270:Naloxone; D004399:Dynorphins; D003913:Dextroamphetamine