Enhanced oral activity responses to intrastriatal SKF 38393 and m-CPP are attenuated by intrastriatal mianserin in neonatal 6-OHDA-lesioned rats.

Autor: Plech, A., Brus, R., Kostrzewa, R., Kalbfleisch, J.
Zdroj: Psychopharmacology; 1995, Vol. 119 Issue 4, p466-473, 8p
Abstrakt: Enhanced oral activity is induced in neonatal 6-hydroxydopamine- (6-OHDA-) lesioned rats by systemic administration of the dopamine (DA) D receptor agonist SKF 38393 and serotonin (5-HT) 5-HT agonist m-chlorophenylpiperazine ( m-CPP). The DA D receptor antagonist SCH 23390 effectively attenuates the effect of SKF 38393 but not m-CPP. The 5-HTantagonist mianserin attenuates the effects of both m-CPP and SKF 38393, suggesting that DA agonist effects are mediated by 5-HT neurochemical systems. To test whether DA and 5-HT agonist effects and interactions might occur within the neostriatum, rats were implanted with permanent injection cannulae, with tips in the ventral striatum. One group of rats was lesioned at 3 days after birth with 6-OHDA HBr (100 µg salt form, in each lateral ventricle; desipramine HCl pretreatment, 20 mg/kg IP, base form, 1 h), while controls received the vehicle in place of 6-OHDA. Cannulae were implanted when rats weighed 200-250 g. During a 1-h observation session SKF 38393 (5 nmol per side) produced 74.3±19.2 oral movements in intact rats and 310.7±97.0 oral movements in 6-OHDA-lesioned rats. m-CPP (10 nmol per side) produced 72.6±15.1 and 274.5±65.0 oral movements in these respective groups. These responses were several-fold greater than the 25.3±7.3 and 41.8±9.5 oral movements in the same groups after saline (0.5 µl per side) ( P<0.05). Mianserin (6 nmol per side) alone had no effect on oral activity but attenuated responses to both SKF 38393 and m-CPP in intact and 6-OHDA-lesioned rats. These findings demonstrate that enhanced oral activity responses are produced by intrastriatal SKF 38393 and m-CPP in neonatal 6-OHDA-lesioned rats. Also, when the 5-HT receptor antagonist mianserin was administered intrastriatally, induction of oral activity by the DA D agonist SKF 38393 was attenuated. These findings indicate that ventral striatum represents at least one brain focus at which DA and 5-HT systems interact to modulate oral activity in rats. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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