Selective agonists for Dl -like and DS-like dopamine receptors can interact synergistically to enhance each other’s actions on locomotion and behavior in experimental animals. Clinically, the combination of the D2 agonist bromocriptine with L-dopa (which has pronounced Dl effects) is a highly effective treatment for Parkinson’s disease. The mechanisms underlying this important receptor interact...

UNLABELLED The senses of hearing and balance are subject to modulation by efferent signaling, including the release of dopamine (DA). How DA influences the activity of the auditory and vestibular systems and its site of action are not well understood. Here we show that dopaminergic efferent fibers innervate the acousticolateralis epithelium of the zebrafish during development but do not directl...

Neuropeptide and immediate early gene expression in striatonigral neurons of the normosensitive striatum is induced by mixed D1/D2 receptor agonists and indirect dopamine agonists, such as cocaine and amphetamine. Both D1 and D2 receptor antagonists block these events. In contrast, the partial D1 agonist, SKF-38393, does not evoke striatonigral gene expression in intact rats. These findings hav...

Dopamine is known to play roles in the processing of emotion. To test whether dopamine has effects on synaptic plasticity in emotion-processing areas, I examined callosally-evoked field potentials in coronal slices of rat anterior cingulate cortex(ACC)when low-frequency stimulation(LFS)was applied to corpus callosum as a conditioning stimulus. Neither dopamine nor the D2 agonist, quinpirole, ha...

Lead treatment via drinking water for 3 to 6 weeks at 250 ppm was found to significantly decrease the number of spontaneously active dopamine (DA) neurons in both the substantia nigra and ventral tegmental area that were recorded using standard extracellular electrophysiological recording techniques. Lead exposure did not affect the discharge rate or discharge pattern of these DA neurons. No si...

Extracellular single unit recording and microiontophoretic techniques were used to determine the sensitivities and interactions of D, and D, dopamine (DA) receptors in the caudate putamen (CPU) of rats that were denervated of DA by intraventricular injections of the catecholamine neurotoxin 6-hydroxydopamine (B-OHDA). Seven to 10 d after the 6-OHDA injection, DA levels in the ipsilateral CPU we...

Variability is a functional and modifiable component of behavior that is necessary for learning or behavior change to occur. An appreciation of drug effects on reinforced variability could contribute to a fuller understanding of potential drug effects on behavior change. Dopamine agonists were examined under conditions that produced low and high levels of variability. In Experiment 1, D-ampheta...

Earlier we reported defects in D1 receptor function in renal proximal tubules (RPTs) of aged Fischer 344 (F344) and obese Zucker rats. However, the defects in the receptor function in RPTs of obese Zucker rats do not pass onto primary cultures of RPTs from these animals. Here, we determined whether the defects in D1 receptor function in RPTs of aged F344 rats pass onto the primary cultures. RPT...

Asghar, Mohammad, Tahir Hussain, and Mustafa F. Lokhandwala. Overexpression of PKCI and contributes to higher PKC activity in the proximal tubules of old Fischer 344 rats. Am J Physiol Renal Physiol 285: F1100–F1107, 2003. First published August 5, 2003; 10.1152/ajprenal.00198.2003.—Previously, we reported that natriuretic and diuretic response to dopamine is diminished in old Fischer 344 rats,...