The effects of apomorphine and methylphenidate on thought disorder, as measured by the Thought Disorder Index, in schizophrenic patients and in normal controls were evaluated. Methylphenidate, but not apomorphine, increased thought disorder in patients. Neither drug significantly increased thought disorder in controls.
The neural mechanisms mediating the ontogeny of behavioral sensitization are poorly understood. The purpose of the present study was to determine the role of the D1 receptor for the induction of dopamine agonist-induced behavioral sensitization during the preweanling period. In the first experiment, the early ontogeny of R-propylnorapomorphine (NPA)-induced… (More)
Dopamine (DA) receptor inactivation produces opposing behavioral effects across ontogeny. For example, inactivating DA receptors in the dorsal striatum attenuates DA agonist-induced behaviors of adult rats, while potentiating the locomotor activity of preweanling rats. The purpose of this study was to determine if DA receptor inactivation potentiates the DA… (More)
There is suggestive evidence that the neural mechanisms mediating one-trial and multi-trial behavioral sensitization differ, especially when the effects of various classes of dopamine (DA) agonists are examined. The purpose of the present study was to determine the role of the D2 receptor for the induction of one-trial and multi-trial methamphetamine… (More)
Inactivating dopamine (DA) receptors in the caudate-putamen (CPu) attenuates basal and DA agonist-induced behaviors of adult rats while paradoxically increasing the locomotor activity of preweanling rats. The purpose of this study was to determine (a) whether D1 or D2 receptor inactivation is responsible for the elevated locomotion shown by preweanling rats… (More)
gamma-Butyrolactone (GBL) potently inhibits stereotyped behavior induced by indirect (amphetamine and methylphenidate) and direct (apomorphine) dopamine agonists. Amphetamine induces a dose-response partial reversal of the GBL effect. The GABA antagonist, bicuculline, only partially reverses the GBL inhibition of apomorphine activity, indicating that GBL… (More)