Effect of dopaminergic drugs on the reserpine-induced lowering of hippocampal theta wave frequency in rats.
The effects of dopaminergic drugs on the lowering of hippocampal theta wave frequency induced by reserpine 1 mg/kg s.c. were examined. Sibutramine (monoamine reuptake inhibitor) 10 mg/kg p.o., methamphetamine (monoamine releaser) 1 mg/kg, quinpirole (dopamine D2 receptor agonist) 10 mg/kg i.p., and SKF 38393 (dopamine D1 receptor agonist) 10 mg/kg i.p. each antagonized the reserpine-induced lowering of hippocampal theta wave frequency in rats. Moreover, the combined administration of SKF 38393 1 mg/kg i.p. and quinpirole 1 mg/kg i.p. synergistically antagonized a reserpine-induced lowering of this frequency. Dosulepin, amitriptyline, and desipramine, which are weak inhibitors of dopamine reuptake, each had little effect on the reserpine-induced lowering of theta wave frequency at a dose of 40 mg/kg p.o. Furthermore, atropine (muscarinic anticholinergic drug) 20 mg/kg p.o. decreased theta wave power in the low-frequency range following a shift to the lower range by reserpine. A positive correlation was observed for each of the above drugs between a reversal of reserpine-induced lowering of theta wave frequency and a reversal of impairment of reserpine-induced conditioned avoidance responses (ACAR) in rats. These results suggest that the reserpine-induced lowering of hippocampal theta wave frequency plays a role in the impairment of reserpine-induced ACAR, and that dopamine D1 and D2 receptors play important roles in antagonizing this lowering of frequency.
Nakagawa
T
T
Central Research Institute, Kaken Pharmaceutical Co. Ltd., Kyoto, Japan.
Ukai
K
K
Ohyama
T
T
Gomita
Y
Y
Okamura
H
H
D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine / Q000494:pharmacology; D000818:Animals; D014150:Antipsychotic Agents / Q000494:pharmacology*; D001285:Atropine / Q000494:pharmacology; D016642:Bupropion / Q000494:pharmacology; D003503:Cyclobutanes / Q000494:pharmacology; D003891:Desipramine / Q000494:pharmacology; D015259:Dopamine Agents / Q000494:pharmacology*; D018491:Dopamine Agonists / Q000494:pharmacology; D006624:Hippocampus / Q000187:drug effects* / Q000502:physiology; D008297:Male; D008694:Methamphetamine / Q000494:pharmacology; D019257:Quinpirole / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D011954:Receptors, Dopamine / Q000502:physiology; D012110:Reserpine / Q000494:pharmacology*; D013826:Theta Rhythm / Q000187:drug effects*
D014150:Antipsychotic Agents; D003503:Cyclobutanes; D015259:Dopamine Agents; D018491:Dopamine Agonists; D011954:Receptors, Dopamine; D016642:Bupropion; D019257:Quinpirole; D008694:Methamphetamine; D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; D001285:Atropine; D012110:Reserpine; D003891:Desipramine; C058254:sibutramine