Dopamine supersensitivity occurs in schizophrenia and other psychoses, and after hippocampal lesions, antipsychotics, ethanol, amphetamine, phencyclidine, gene knockouts of Dbh (dopamine beta-hydroxylase), Drd4 receptors, Gprk6 (G protein-coupled receptor kinase 6), Comt (catechol-O-methyltransferase), or Th-/-, DbhTh/+ (tyrosine hydroxylase), and in rats born by Cesarean-section. The functiona...

INTRODUCTION The cardinal pathological feature of Parkinson's disease (PD) is progressive loss of dopaminergic neurons. Since dopamine transporter (DAT) is a protein located presynaptically on dopaminergic nerve terminals, radioligands that bind to these sites are promising radiopharmaceuticals for evaluation of the integrity of the dopamine system. This study using positron emission tomography...

The present study investigated the effects of dopamine on chloride transport across cultured rat caudal epididymal epithelium. The results showed that dopamine induced a biphasic short-circuit current (Isc) in a concentration-dependent manner. The dopamine-induced response consisted of an initial rapid spike followed by a sustained phase. The alpha and beta adrenoreceptor inhibitors, phentolami...

In Heteropneustes fossilis, administration of a single dose (0.15 micrograms/g body weight, i.p.) of [D-Ala6,Gly10]-gonadotrophin-releasing hormone analogue (GnRHa) induced ovulation (in 35 of 35 fish) when mild-stripped at 16 h. Plasma gonadotrophin II (GTH II) levels showed a highly significant increase at 2, 4, 8, 12 and 16 h with the peak at 8 h. Plasma cortisol, progesterone and testostero...

Movement is accompanied by changes in the degree to which neurons in corticobasal ganglia loops synchronize their activity within discrete frequency ranges. Although two principal frequency bands--beta (15-30 Hz) and gamma (60-90 Hz)--have been implicated in motor control, the precise functional correlates of their activities remain unclear. Local field potential (LFP) recordings in humans with...

Since the unexpected discovery of the antipsychotic activity of chlorpromazine, a variety of therapeutic agents have been developed for the treatment of schizophrenia. Despite differences in their activities at various neurotransmitter systems, all clinically effective antipsychotics share the ability to interact with D2 class dopamine receptors (D2R). D2R mediate their physiological effects vi...

In lower vertebrates, cone retinomotor movements occur in response to changes in lighting conditions and to an endogenous circadian clock. In the light, cone myoids contract, while in the dark, they elongate. In order to test the hypothesis that melatonin and dopamine may be involved in the regulation of cone movement, we have used an in vitro eyecup preparation from Xenopus laevis that sustain...

The aim of the present study was to clarify whether pharmacological preconditioning with dopamine protects the heart against ischemia and whether this effect is mediated through dopaminergic receptors (D1 and D2) or alpha1-adrenoceptors. Isolated perfused rat hearts were either non-preconditioned, preconditioned with 5 min ischemia, or treated for 5 min with dopamine (1, 5 or 10 microM) before ...

Background Attention deficit hyperactivity disorder (ADHD) is a common behavioral disorder that affects 8-12% of school-age children. Several environmental and genetic factors play a role in the etiology of this disease. One of the genetic factors involved is dopamine beta-hydroxylase (DBH) gene, which plays an essential role in catecholamine synthesis by converting dopamine into norepinephrine...

1. Acebutolol, a beta1-receptor blocker, has, at a daily dose of 800 mg, a mild but significant anti-hypertensive effect in moderate sustained essential hypertension with normal or low plasma renin activity. 2. Prediction of its anti-hypertensive effect is better based on the evaluation of the sympathetic nervous system responsiveness to head-up tilt than on the evaluation of plasma renin activ...