C A Marin

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The effects of chronic D-1 and/or D-2 dopamine (DA) receptor blockade on a putative D-1 DA receptor-mediated behavioral function was studied in rats treated for 21 days with the selective D-1 antagonist SCH 23390, the predominantly D-2 antagonist haloperidol, or the combination of both drugs at the same daily doses. Four days after the last drug dose, the(More)
The systemic administration of the N-methyl-D-aspartate (NMDA) receptor antagonist, MK801 ((+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine) , has previously been found to reverse the motor response alterations that develop during long-term levodopa treatment of parkinsonian rats. To determine whether co-administration of MK801 with levodopa(More)
In two experiments, the effects of repeated intermittent administration of a relatively high dose of apomorphine (5 mg/kg) on locomotor activity and/or stereotypic behavior in rats was determined. In Experiment 1, male rats were given ten subcutaneous (SC) injections of apomorphine or vehicle and tested for locomotor activity and stereotypy. The first nine(More)
Striatal dynorphin-containing neurons receive dopaminergic inputs from the substantia nigra pars compacta and project primarily to the substantia nigra pars reticulata and entopeduncular nucleus. These neurons mainly express dopamine (DA) D1 receptors and thus dynorphin system stimulation might be expected largely to influence D1 receptor agonist or(More)
Striatal enkephalin-containing neurons receive dopaminergic inputs from the substantia nigra and project to the external segment of globus pallidus. These neurons express primarily dopamine (DA) D-2 receptors. Accordingly, stimulation of enkephalinergic transmission might be expected to influence mainly D-2 receptor agonist or antagonist effects on motor(More)
Recent evidence suggests that behavioral supersensitivity to dopamine (DA) agonists observed in chronic neuroleptic-treated animals might be related to changes in synaptic morphology and density. The aim of this study was to test this hypothesis using Western blotting to determine the striatal synaptophysin levels in rats chronically treated with(More)
The effect of selective dopamine D1 and D2 receptor agonists on chronic haloperidol-treated rats was studied. Haloperidol treatment produced a 77% increase in apomorphine-induced sterotypy. The administration of the selective dopamine D1 receptor agonist SKF38393 alone or in combination with the selective dopamine D2 receptor agonist quinpirole attenuated(More)
The contribution of dopaminergic mechanisms to the generalization of epileptic activity was studied in rats given pilocarpine after pretreatment with selective dopamine agonists. At the dose of 200 mg/kg, pilocarpine produced limbic stereotypes but not convulsions or seizure-related brain damage. Pilocarpine, 200 mg/kg, following pretreatment with the D1(More)
Behavioral and biochemical responses to D1 and D2 dopamine (DA) agonists were used to evaluate the participation of striatal peptidergic mechanisms in the motor function alterations that attend chronic neuroleptic treatment. Rats, given haloperidol (1 mg/kg, i.c.) for 21 consecutive days, were randomly allocated to one of the following treatments: the D1(More)
The 24-h growth hormone secretory pattern and GH response to growth hormone releasing hormone, the alpha 2-adrenoceptor agonist clonidine and the somatostatin-analogue SMS 201-995 were evaluated in 9 patients with Alzheimer's disease and 9 age- and body body-matched control subjects. The secretory profile did not differentiate between patients and controls.(More)