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G F Wooten

Publications and source records attributed to G F Wooten.

17 recordsLinked to original sources
PubMed1992

The time course of changes in D1 and D2 receptor binding in the striatum following a selective lesion of striatonigral neurons.

The suicide transport agent volkensin was used to produce a selective lesion of striatonigral projection neurons and the time course of changes in binding at striatal D1 and D2 receptors analyzed. Both show a time-dependent decrease with two-thirds of the total change occurring within the first 10 days and a greater decrease in D1 receptor density at all time points. Our results confirm selective localization of D1 receptors to striatonigral neurons and are consistent with localization of some striatal D2 receptors to striatonigral neurons.

Animals↗
PubMed1992

Quantitative autoradiography of hemicholinium-3 binding sites in human amygdala.

We report the binding properties and subnuclear localization of [3H]hemicholinium-3 binding sites in human amygdala using quantitative autoradiography. Specific binding was saturable and high affinity (apparent Kd 2-11 nM). Binding was highest in the basolateral nucleus which receives dense cholinergic innervation from the basal forebrain. Binding closely approximated acetylcholinesterase reactivity. These data support [3H]hemicholinium-3 as a quantitative marker for cholinergic terminals in human brain.

Aged↗
PubMed1992

D2 dopaminergic regulation of striatal preproenkephalin mRNA levels is mediated at least in part through cholinergic interneurons.

The effect of administration of the muscarinic antagonist scopolamine on the increase in striatal preproenkephalin (PPE) mRNA following a 6-hydroxydopamine (6-OHDA) lesion or chronic D2 dopamine (DA) antagonist treatment was examined by dot-blot hybridization. Administration of scopolamine dose-dependently attenuated the 6-OHDA lesion-induced increase in striatal PPE mRNA. Administration of the D2 DA antagonist eticlopride to naive rats increased striatal PPE mRNA in a dose- and time-dependent fashion. Chronic coadministration of scopolamine attenuated the eticlopride-induced increase in striatal PPE mRNA. Chronic administration of scopolamine alone did not alter striatal PPE mRNA levels. In contrast, chronic administration of eticlopride, scopolamine or the two combined decreased striatal preprotachykinin (PPT) mRNA to the same extent, suggesting that there was no direct interaction between D2 dopaminergic and cholinergic mechanisms in the regulation of striatal PPT mRNA. These data indicate that DA differentially regulates striatal PPE and PPT mRNA and suggest that dopaminergic regulation of striatal PPE mRNA is mediated in part through D2 DA effects on striatal cholinergic neurons.

Acetylcholine↗
PubMed1992

Differential regulation of striatal preproenkephalin mRNA by D1 and D2 dopamine receptors.

The effect of administration of subtype selective dopamine (DA) agonists on the 6-hydroxydopamine (6-OHDA) lesion-induced increase of striatal preproenkephalin (PPE) mRNA was examined by dot-blot hybridization. Eight days following a unilateral 6-OHDA lesion of the substantia nigra pars compacta (SNc), PPE mRNA levels in the ipsilateral striatum were increased approximately two-fold. Administration of the D2 DA agonist, quinpirole, dose-dependently attenuated the 6-OHDA lesion-induced increase in striatal PPE mRNA. The effect of quinpirole was blocked by coadministration of the D2 DA antagonist eticlopride. In contrast, administration of the D1 DA agonist, SKF 38393, either dose-dependently augmented or had no effect on the 6-OHDA lesion-induced increase in striatal PPE mRNA. In the contralateral striatum, administration of quinpirole decreased PPE mRNA, while administration of SKF 38393 increased PPE mRNA compared to sham lesioned control levels. These data suggest the action of DA at D1 and D2 DA receptors differentially regulates striatal PPE mRNA levels and the apparent inhibition of ENK biosynthesis by DA is mediated via an interaction with D2 DA receptors.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed1976

Regulation of rat adrenal dopamine beta-hydroxylase. II. Receptor interaction in the regulation of enzyme synthesis and degradation.

Rat adrenal gland dopamine beta-hydroxylase is under neuronal regulation from the splanchnic nerve and hormonal control via adrenal cortical glucocorticoids. The regulatory systems act in different ways; neuronal stimuli induce dopamine beta-hydroxylase synthesis while hormonal stimulation inhibits enzyme degradation. Despite these mechanistic differences, both systems require a normally innervated cholinergic receptor to exert their effect. The enzyme response to either neural stimulation or ACTH administration is blocked by splanchnic denervation. Glucocorticoid stimulation of dopamine beta-hydroxylase, however, can occur after adrenal denervation, suggesting that ACTH acts on a receptor which requires splanchnic innervation, but glucocorticoids act distal to the receptor. Similar results were obtained when the effect of these manipulations were studied on phenylethanolamine N-methyltransferase, another enzyme in the catecholamine biosynthetic pathway. A model attempting to unify these and earlier findings is presented, in which the splanchnic nerve is involved in regulating both adrenal cortical glucocorticoidogenesis (by allowing ACTH to act on glucocorticoid synthesis) and adrenal medullary catecholamine biosynthesis (by induction of enzyme synthesis.).

Adrenal Glands↗
PubMed1976

Serum dopamine-beta-hydroxylase activity in rat during post-natal development.

Rat serum dopamine-beta-hydroxylase (DBH) activity is quite high in the immediate post-natal period reaching peak activity (75 units) at 16 days of age. Activity then decreases rapidly over the following weeks to approach adult levels (10 units) by seven weeks of age. Also, specific activity of DBH in heart increased rapidly during the first 2 1/2 weeks of life attaining adult levels by 18 days of age. In contrast, heart weight and total DBH activity in whole heart increased in a coordinate fashion at a relatively constant rate throughout the first seven weeks of life. Serum levels of non-copper sensitive endogenous inhibitor (s) of DBH increased throughout the first seven weeks of life while no change in copper sensitive inhibition was observed. Also, the rapid phase of decrease in serum DBH activity corresponded to the period of the most rapid increase in body weight.

Animals↗
PubMed1975

Regulation of dopamine beta-hydroxylase in rat adrenal glands.

Rat adrenal gland levels of dopamine beta-hydroxylase are subject to dual control. Activation of the splanchnic nerves to the adrenal medulla by reserpine induces the synthesis of dopamine beta-hydroxylase without altering the rate of enzyme degradation. In contrast, hypophysectomy causes a decline in steady state dopamine beta-hydroxylase levels by first accelerating the rate of degradation, then by slowing the rate of enzyme synthesis as well. Adrenocorticotropic hormone administration partially reversed the effect of hypophysectomy on dopamin beta-hydroxylase degradation. These findings suggest that the trans-synaptic factors controlling dopamine beta-hydroxylase induction act by a different mechanism (enzyme synthesis) than the hormonal controls regulating steady state levels (enzyme degradation). Thus, active inhibition of enzyme degradation may be an important control in maintenance of steady state enzyme levels.

Adrenal Glands↗