Species difference in the modulatory effect of kappa agonist on 5-HT release from ground squirrel and rat hippocampus.
Inclusion of the kappa agonist U50488 in the perifusion medium enhanced K(+)-stimulated 5-HT release from ground squirrel hippocampal slices, but reduced 5-HT outflow in both young and old rats' hippocampal slices. The stimulatory effect of U50488 on 5-HT release from ground squirrel hippocampus was not significantly attenuated by the non-specific opioid antagonist naloxone (10(-5) M), but was completely reversed by the specific kappa antagonist nor-BNI (10(-6)M), and the voltage-dependent sodium channel blocker TTX (10(-6)M). In contrast, the inhibitory effect of U50488 on 5-HT release from the young rat hippocampus was attenuated by naloxone (10(-6)M), but not by nor-BNI (10(-6)M) or TTX (10(-6)M). These results illustrate a significant species difference in the modulatory effect of opioids on neurotransmitter release in the hippocampus.
Department of Zoology, University of Alberta, Edmonton, Canada.
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D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer; D000375:Aging / Q000378:metabolism; D000818:Animals; D004305:Dose-Response Relationship, Drug; D005260:Female; D006624:Hippocampus / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D009270:Naloxone / Q000494:pharmacology; D009271:Naltrexone / Q000031:analogs & derivatives / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D011759:Pyrrolidines / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley / Q000378:metabolism*; D017473:Receptors, Opioid, kappa / Q000819:agonists*; D012589:Sciuridae / Q000378:metabolism*; D012701:Serotonin / Q000378:metabolism*; D013045:Species Specificity; D013779:Tetrodotoxin / Q000494:pharmacology
D011759:Pyrrolidines; D017473:Receptors, Opioid, kappa; D012701:Serotonin; D009270:Naloxone; C051844:norbinaltorphimine; D013779:Tetrodotoxin; D009271:Naltrexone; D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer; D011188:Potassium