Systemic injection of the D1 dopamine receptor antagonist SCH 23390 produces catalepsy that is of lesser magnitude in neonatal than in adult rats. The present experiments were conducted in order to determine if SCH 23390 would produce catalepsy in neonatal rats following intrastriatal injection and if the ontogenetic pattern of catalepsy induced by intrastriatal SCH 23390 would be similar to the pattern observed with systemic injections. Rat pups (11 or 28 days of age) were microinjected unilaterally with SCH 23390 (0.2, 1, 5 or 10 μg) and tested for catalepsy using the forepow-on-horizontal-bar test. The results demonstrated that robust catalepsy occurred at both ages following intrastriatal injection and that catalepsy induced by 5 μg SCH 23390 was of lesser magnitude in 11-day-olds than in 28-day-olds. A separate study assessed the distribution of [3H]SCH 23390 (5 μg) following intrastriatal injection in 28-day-olds. Results of the distribution study indicated that [3H]SCH 23390 was localized primarily within the striatum. Taken together, these results suggest that the striatal mechanisms for catalepsy produced by D1 receptor blockade are present, but not fully mature, in preweanling rat pups.
|Number of pages||6|
|Journal||Pharmacology Biochemistry and Behavior|
|State||Published - Dec 1991|
Bibliographical noteFunding Information:
The authors thank Dr. Arthur Nonneman for advice on the histological techniques and for helpful comments on an earlier version of this manuscript. Also, we thank Cynthia Crawford for advice and assistance with the surgical procedure. This research was supported in part by USPHS grant DA05312 awarded to M.T.B.
- D dopamine receptor
- SCH 23390
ASJC Scopus subject areas
- Clinical Biochemistry
- Biological Psychiatry
- Behavioral Neuroscience