Cocaine binding sites in mouse striatum, dopamine autoreceptors, and cocaine-induced locomotion.
BALB/cByJ mice received cocaine (25 mg/kg IP) once a day for 3 days, resulting in a greater locomotor response to cocaine on day 3 than on day 1. On day 4, a dose (0.03 mg/kg SC) of apomorphine, targeted at dopamine autoreceptors, caused the same degree of locomotor depression in cocaine- as in saline-pretreated mice. In addition, no change was found in either the affinity or density of cocaine binding sites in their striatum as measured by the binding of [3H]CFT. C57BL/6ByJ, mice displayed a greater locomotor response to cocaine than BALB/cByJ mice, but had the same number of striatal [3H]CFT binding sites with the same affinity. Factors other than striatal cocaine binding sites, or dopamine autoreceptors as measured by apomorphine-induced depression of locomotion, should be considered for the explanation of the enhancement of the locomotor response upon daily cocaine administration in BALB/cByJ mice, or for the different locomotor response to cocaine of this strain compared with the C57BL/6ByJ strain of mice.
Reith
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Division for Neurochemistry, N. S. Kline Institute for Psychiatric Research, Orangeburg, NY 10962.
Selmeci
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D000375:Aging / Q000378:metabolism; D000818:Animals; D001058:Apomorphine / Q000494:pharmacology; D003042:Cocaine / Q000031:analogs & derivatives / Q000378:metabolism* / Q000494:pharmacology; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D009043:Motor Activity / Q000187:drug effects*; D011954:Receptors, Dopamine / Q000187:drug effects / Q000378:metabolism*; D011957:Receptors, Opioid / Q000378:metabolism*
D011954:Receptors, Dopamine; D011957:Receptors, Opioid; C021279:(1R-(exo,exo))-3-(4-fluorophenyl)-8-methyl-8- azabicyclo(3.2.1)octane-2-carboxylic acid, methyl ester; D003042:Cocaine; D001058:Apomorphine