Basal local cerebral glucose utilization is not altered after behavioral sensitization to quinpirole.
Sensitization to psychostimulants results in a behavioral response of a greater magnitude than that produced by a given single dose. Previously, we have shown that sensitization to the D(2)/D(3) dopamine receptor agonist quinpirole produces alterations in quinpirole-stimulated local cerebral glucose utilization (LCGU) in ventral striatal and limbic cortical regions. To determine whether basal neuronal activity is altered in the sensitized animal, this study examined the effects of a sensitizing course of quinpirole on basal neuronal activity using the [(14)C]-2-deoxyglucose (2-DG) method in rats with verified sensitization. Adult, male Long-Evans rats (n = 7 or 10/group) were subjected to 10 injections of quinpirole (0.5 mg/kg, s.c.) or saline administered every 3rd day. Sensitization was verified on the basis of locomotor activity. The 2-DG procedure was performed in freely moving rats 3 days after the last quinpirole injection. LCGU was determined by quantitative autoradiography. No alterations in basal LCGU were detected in quinpirole-sensitized rats compared to those treated with saline. The present finding suggests that either the basal activity of very discrete populations of neurons is affected by sensitization to quinpirole that are not likely to be detected by the 2-DG method, or that the neurobiological changes that result in the sensitized behavioral response affect only stimulated, but not basal, neuronal activity.
Richards
Toni L
TL
Department of Pharmacology, Toxicology, and Therapeutics, University of Kansas Medical Center, Kansas City, KS 66160, USA.
Pazdernik
Thomas L
TL
Levant
Beth
B
D000818:Animals; D001345:Autoradiography; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology; D001667:Binding, Competitive / Q000187:drug effects / Q000502:physiology; D000697:Central Nervous System Stimulants / Q000494:pharmacology; D002540:Cerebral Cortex / Q000187:drug effects* / Q000378:metabolism*; D003847:Deoxyglucose / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism; D018491:Dopamine Agonists / Q000494:pharmacology*; D004734:Energy Metabolism / Q000187:drug effects / Q000502:physiology; D005947:Glucose / Q000378:metabolism*; D008297:Male; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D019257:Quinpirole / Q000494:pharmacology*; D051381:Rats; D020318:Rats, Long-Evans; D017448:Receptors, Dopamine D2 / Q000819:agonists* / Q000378:metabolism; D012680:Sensitivity and Specificity
D000697:Central Nervous System Stimulants; D018491:Dopamine Agonists; D017448:Receptors, Dopamine D2; D019257:Quinpirole; D003847:Deoxyglucose; D005947:Glucose; D004298:Dopamine