The effects of dopaminergic drugs in the ventral hippocampus of rats in the nicotine-induced anxiogenic-like response.
Nicotine an active alkaloid of tobacco has dopaminergic properties. The drug alters anxiety-like behavior in rodents. Ventral hippocampus (VHC) may be a site for modulation of anxiety-like behaviors. The possible involvement of ventral hippocampal dopaminergic receptor mechanism in the nicotine influence on anxiogenic-like response has been investigated in the present study. The effects of apomorphine, sulpiride and SCH23390 on nicotine response in elevated plus maze in rats have been investigated. Intraperitoneal administration of nicotine (0.6mg/kg) decreased percentage of open arm time (%OAT) but not percentage of open arm entries (%OAE) and locomotor activity, indicating an anxiogenic-like response. Intra-hippocampal injection (intra-VHC) of apomorphine, a D(1)/D(2) dopamine receptor agonist (0.1 and 0.2microg/rat) also caused anxiogenic-like effects, but the drug blocked that of nicotine. Intra-VHC administration of the D(2) receptor antagonist, sulpiride (1, 2.5 and 5microg/rat) or the D(1) receptor antagonist, SCH23390 (0.01, 0.1 and 1microg/rat) did not elicit any response. However, pretreatment with sulpiride (1microg/rat) or SCH23390 (0.1microg/rat) decreased nicotine's effect. The results may indicate a modulatory effect for the D(1) and D(2) dopamine receptors of VHC in the anxiogenic-like response induced by nicotine.
Zarrindast
Mohammad-Reza
MR
Department of Pharmacology, School of Advanced Medical Technologies and Iranian National Center for Addiction Studies, Tehran University of Medical Sciences, Tehran, Iran. zarinmr@ams.ac.ir
Naghdi-Sedeh
Nima
N
Nasehi
Mohammad
M
Sahraei
Hedayat
H
Bahrami
Farideh
F
Asadi
Fereshteh
F
D000818:Animals; D001007:Anxiety / Q000378:metabolism* / Q000523:psychology; D001058:Apomorphine / Q000494:pharmacology; D001552:Benzazepines / Q000494:pharmacology; D015259:Dopamine Agents / Q000494:pharmacology*; D065127:Dopamine D2 Receptor Antagonists; D006624:Hippocampus / Q000187:drug effects* / Q000503:physiopathology; D008297:Male; D018782:Maze Learning / Q000187:drug effects; D009043:Motor Activity / Q000187:drug effects; D009538:Nicotine / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D017447:Receptors, Dopamine D1 / Q000819:agonists / Q000037:antagonists & inhibitors / Q000502:physiology; D017448:Receptors, Dopamine D2 / Q000819:agonists / Q000502:physiology; D013469:Sulpiride / Q000494:pharmacology
D001552:Benzazepines; D015259:Dopamine Agents; D065127:Dopamine D2 Receptor Antagonists; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; C534628:SCH 23390; D009538:Nicotine; D013469:Sulpiride; D001058:Apomorphine