Robert L. Patrick

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Rats were treated twice daily either with saline or d-amphetamine (5 mg/kg) for 5 days. When challenged approximately 15 days later with an injection of 0.5 mg/kg amphetamine, the chronic amphetamine animals showed (1) an augmented release of dopamine in the caudate nucleus in vivo and (2) an increase in stereotyped behavior compared to the chronic saline(More)
Three extrathalamic subcortical inputs to the part of the cerebral cortex that is known to receive thalamic fibers in the turtle were examined in the present study. Direct projections from the locus coeruleus, the superior medial raphe nucleus, and a wide area of the basal telencephalon that lies ventromedial to the globus pallidus were demonstrated with(More)
Amphetamine and phenylethylamine stimulate dopamine synthesis in rat brain striatal synaptosomes via a calcium- and tyrosine-dependent mechanism. The similarity of this stimulation to that produced by depolarizing concentrations of veratridine, along with the non-additivity of maximally stimulating concentrations of amphetamine and veratridine, suggests(More)
The effect of unilateral intranigral cannabinoid receptor stimulation on rotational behavior was explored. The potent cannabinoid agonist CP 55,940 (5 and 10 micrograms/0.5 microliter) induced contralateral turning when microinjected unilaterally into the substantia nigra pars reticulata. In addition, the cannabinoid agonist markedly attenuated the(More)
The present studies were carried out to analyze the neurochemical and behavioral effects of peripheral sigma ligand administration in the rat. Based upon previous studies which showed an increase in turning behavior following unilateral intranigral administration of sigma ligands, we determined the effects of two sigma ligands, 1,3-di-o-tolylguanidine (DTG)(More)
Cannabinoid receptors in the brain are highly concentrated in the basal ganglia, which is in accordance with their well known effects on motor behavior. In this study, rats with 6-hydroxydopamine lesions of the nigrostriatal pathway were implanted with cannulae in the striatum, globus pallidus and substantia nigra. The effect of unilateral infusion of the(More)
The present studies were carried out to determine if tyrosine hydroxylase phosphorylation in rat brain striatal synaptosomes is activated by dibutyryl cyclic AMP treatment. Incubation of synaptosomes with [32P]orthophosphate, followed by immunoprecipitation and sodium dodecyl sulfate polyacrylamide gel electrophoresis, produced a band of radioactivity(More)
The regulation of motor behavior by mu, delta and kappa opiate receptors in the substantia nigra was examined. Unilateral microinjections of specific mu (DAGO), delta (DPDPE) and kappa (U-50,488H) ligands into the substantia nigra pars reticulata of rats produced dose-dependent contralateral turning. The opiate antagonist naloxone blocked these effects,(More)