The present study sought to determine, in more detail, the effects of an unselective and a selective adenosine A(2A) receptor blockade on catalepsy induced by a blockade of dopamine D1 or D2 receptors in rats. The results demonstrated that systemic administration of the unselective A1/A2 receptor antagonist, theophylline and the selective A(2A) receptor antagonist, CSC potently reversed catalep...

Progress in neuroscience research often involves animals, as no adequate alternatives exist to animal models of living systems. However, both the physiological characteristics of the species used and the effects of anesthesia raise questions of common concern. Here, we demonstrate the confounding influences of these effects on tracer binding in positron emission tomography (PET). We determined ...

Dopamine agonists facilitate, and antagonists inhibit, conditioned preparatory behaviors in rats. Similar effects are demonstrated on an unconditioned preparatory behavior: predatory search and contact of a moving artificial prey stimulus. Apomorphine (0.1, 0.2 mg/kg), a direct agonist, had no effect relative to a within-subject injection of saline vehicle but d-amphetamine (0.1 mg/kg), an indi...

The herbicide atrazine (ATR) has a potential toxic effect on the neuronal circuits of the brain, specifically on two major dopaminergic pathways: the nigrostriatal and mesolimbic circuits. In this work, we repeatedly exposed adult male Sprague-Dawley rats to 6 injections of 100 mg ATR/kg of body weight (for two weeks) and one saline injection two days after ATR administration. Locomotor activit...

This study examined the effects of a dopamine D(1) antagonist, SCH23390, infused into the prelimbic-infralimbic areas on the acquisition of a response and visual-cue discrimination task, as well as a shift from a response to a visual-cue discrimination and vice versa. Each test was carried out in a cross-maze. The response discrimination required learning to always turn in the same direction (r...

This study examined the role of dopamine D1-like receptor transmission in the lateral hypothalamus (LH) in flavor preference learning induced by intragastric (IG) infusions of glucose. Rats fitted with gastric catheters were injected daily in the LH with either saline or SCH23390 (12 nmol/brain), 10 min prior to training sessions with a flavor (CS+) paired with IG infusions of 8% glucose and a ...

Place-specific firing by hippocampal and striatal neurons was recorded simultaneously following injection of a D(1) receptor antagonist (SCH23390) and during spatial working memory task performance. SCH23390-induced changes in unit responses were observed during light and dark test conditions. Although hippocampal place field locations were altered by the contextual change, the reliability and ...

In the present study, the effects of intra-locus coeruleus injection of a dopamine D(1) receptor agonist (SKF38393) on naloxone-induced withdrawal signs of morphine-dependent rats were examined. Twenty different withdrawal signs were assessed. The total withdrawal score was calculated and used as an index of withdrawal intensity for comparison. The D(1) agonist and antagonist were injected 15 a...