Me. Stockton et K. Rasmussen, ELECTROPHYSIOLOGICAL EFFECTS OF OLANZAPINE, A NOVEL ATYPICAL ANTIPSYCHOTIC, ON A9 AND A10 DOPAMINE NEURONS, Neuropsychopharmacology, 14(2), 1996, pp. 97-104
This study examined the effects of the novel atypical antipsychotic ol
anzapine (LY170053) on the activity of substantia nigra pars compacta
(A9) and ventral tegmental area (A10) dopamine cells in anesthetized r
ats. Acute administration of olanzapine (10, 20 mg/kg sc) increased th
e number of spontaneously active A10, but not A9, dopamine cells. Chro
nic administration of olanzapine (10, 20 mg/kg/day x 21 days) decrease
d the number of spontaneously active A10, but not A9, dopamine cells.
Administration of the dopamine agonist apomorphine reversed the effect
s of chronic olanzapine on A10 cells, indicating a possible depolariza
tion-inactivation mechanism. In conclusion, olanzapine has selective e
ffects on A10 versus A9 dopamine cells following acute and chronic adm
inistration. These effects of olanzapine on dopamine cells are similar
to the effects observed with clozapine and may play an important role
in the atypical antipsychotic profile of olanzapine.