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T C Rainbow

Publications and source records attributed to T C Rainbow.

At least 55 records · Page 3Linked to original sources
PubMed1983

Modulation by vasoactive intestinal peptide of serotonin receptors in the dorsal hippocampus of the rat brain: an autoradiographic study.

Brain sections of 32 microns from the hippocampus were incubated with tritiated serotonin (5-HT) in the presence or absence of 10(-7) M vasoactive intestinal peptide (VIP). Sections were run for biochemical Scatchard analysis or quantitative autoradiography by means of LKB 3H-Ultrofilm. On sections from dorsal hippocampus, VIP increases the amount of 5-HT1 receptors and decreases the affinity for the ligand. Densities measurements show that this effect is located in a discrete area of the hippocampus, the dorsal subiculum. The present data suggest that some of the neurotransmitter effects of 5-HT in the central nervous system can be modulated by VIP.

Animals↗
PubMed1983

Intrahypothalamic 5,7-dihydroxytryptamine facilitates feminine sexual behavior and decreases [3H]imipramine binding and 5-HT uptake.

5,7-Dihydroxytryptamine (5,7-DHT) injected into the hypothalamus facilitated feminine sexual behavior in ovariectomized, estrogen-treated female rats beginning 9 days post-lesion. 5,7-DHT treatment was associated with decreased [3H]5-HT but not [3H]NE uptake in the whole hypothalamus and with decreased [3H]-imipramine binding in some hypothalamic nuclei. These data provide the first demonstration using chemical lesions that 5-HT neurons may exert tonic inhibition on hormone-mediated feminine sexual behavior.

5,7-Dihydroxytryptamine↗
PubMed1983

Quantitative autoradiography of [3H]nitroimipramine binding sites in rat brain.

We have used the recent tritium-sensitive film method of quantitative autoradiography to localize in rat brain high-affinity binding sites for nitroimipramine (NI), a long-lasting inhibitor of serotonin (5-HT) transport in platelets. The distribution of NI binding sites in rat brain closely parallels the location of 5-HT terminals. There are high concentrations of binding sites in the dorsal and medial raphe nuclei, the basal portion of the mammilary nuclei, the medial forebrain bundle, the olfactory tubercule and the posterior basal nucleus of the amygdala. The association of [3H]NI binding sites with regions having a high content of 5-HT supports the notion that the high-affinity binding site for [3H]NI corresponds to some aspect of the presynaptic uptake site for 5-HT.

Animals↗
PubMed1983

Identification of mineralocorticoid binding sites in rat brain by competition studies and density gradient centrifugation.

A search for mineralocorticoid binding sites in neural tissue was carried out on the basis of competition by two mineralocorticoid antagonists (spironolactone and glycyrrhetinic acid), a mineralocorticoid agonist (9 alpha-fluorocortisol) and a pure glucocorticoid (RU 26988). The hippocampus was selected for these studies, in view of its preferential concentration of binding sites for [3H]-aldosterone (ALDO) and two glucocorticoids: [3H]-corticosterone (CORT) and [3H]-dexamethasone (DEX). Inhibition studies performed with 5 X 10(-4)-5 X 10(-9) M spironolactone and with 5 X 10(-4)-5 X 10(-8) M glycyrrhetinic acid, showed a dose-response reduction of [3H]-ALDO, [3H]-CORT and [3H]-DEX binding, implying that in brain these compounds did not behave as exclusive ALDO antagonists. Two concentrations of 9 alpha-fluorocortisol (5 X 10(-9) and 2.5 X 10(-8) M) preferentially displaced [3H]-ALDO in comparison to [3H]-DEX or [3H]-CORT. Relative binding affinity (RBA) of 9 alpha-fluorocortisol was also higher for the mineralocorticoid than for the glucocorticoids. RU 26988 (5 X 10(-6)-2.5 X 10(-8)M) gave differential inhibition of the three ligands and its RBA for [3H]-DEX site was twice as high as for [3H]-CORT, and three orders of magnitude higher than for [3H]-ALDO binding sites, thus clearly separating sites for gluco- and mineralocorticoids. Further evidence for the presence of separate binding molecules for mineralo- and glucocorticoids in hippocampal cytosol was provided by ultracentrifugation on 16-41% glycerol gradients containing molybdate, which yielded sedimentation values of 9.88 +/- 0.27 for [3H]-DEX (n = 5), 10.48 +/- 0.27 for [3H]-CORT (n = 9) and 11.3 +/- 0.13 for [3H]-ALDO (n = 7).(ABSTRACT TRUNCATED AT 250 WORDS)

Aldosterone↗
PubMed1983

Localization and characterization of [3H]desmethylimipramine binding sites in rat brain by quantitative autoradiography.

The high affinity binding sites for the antidepressant desmethlyimipramine (DMI) have been localized in rat brain by quantitative autoradiography. There are high concentrations of binding sites in the locus ceruleus, the anterior ventral thalamus, the ventral portion of the bed nucleus of the stria terminalis, the paraventricular and the dorsomedial nuclei of the hypothalamus. The distribution of DMI binding sites is in striking accord with the distribution of norepinephrine terminals. Pretreatment of rats with the neurotoxin 6-hydroxydopamine, which causes a selective degeneration of catecholamine terminals, results in 60 to 90% decrease in DMI binding. These data support the idea that high affinity binding sites for DMI are located on presynaptic noradrenergic terminals.

Animals↗
PubMed1982

Quantitative autoradiography of serotonin receptors in the rat brain.

The distribution of serotonin receptors in the rat brain was studied using a new, quantitative autoradiographic technique utilizing tritium-sensitive LKB sheet film, and densitometric analysis of the film images. OD values above 13 were found in the dentate gyrus, subiculum, substantia nigra and ependymal tissue throughout the brain. ODs between 7 and 11 were found in the globus pallidus, anterior hippocampus and CA1 field, dorsal raphe nucleus and interpeduncular nucleus. The lowest densities were observed in the thalamus, cerebellum, and over white matter, between 0.1 and 0.4 OD units. Other brain nuclei have intermediate values. Serotonin receptor distribution is found to correlate with 5-HT levels, corticosteroid and estrogen receptors in some but not all brain regions.

Animals↗
PubMed1982

Minireview: quantitative autoradiography of neurochemicals.

Several new methods have been developed that apply quantitative autoradiography to neurochemistry. These methods are derived from the 2-deoxyglucose (2DG) technique of Sokoloff (1), which uses quantitative autoradiography to measure the rate of glucose utilization in brain structures. The new methods allow the measurement of the rate of cerebral protein synthesis and the levels of particular neurotransmitter receptors by quantitative autoradiography. As with the 2DG method, the new techniques can measure molecular levels in micron-sized brain structures; and can be used in conjunction with computerized systems of image processing. It is possible that many neurochemical measurements could be made by computerized analysis of quantitative autoradiograms.

Animals↗
PubMed1982

Quantitative densitometry of neurotransmitter receptors.

An autoradiographic procedure is described that allows the quantitative measurement of neurotransmitter receptors by optical density readings. This procedure is a modification of the method of Young and Kuhar (1979a). Frozen brain sections are labeled in vitro with [3H]ligands under conditions that maximize specific binding to neurotransmitter receptors. The labeled sections are then placed against the 3H-sensitive LKB Ultrofilm to produce the autoradiograms. These autoradiograms resemble those produced by [14C]deoxyglucose autoradiography (Sokoloff, 1977) and are suitable for quantitative analysis with a densitometer. Muscarinic cholinergic receptors in rat and zebra finch brain and 5-HT receptors in rat brain were visualized by this method. When the proper combination of ligand concentration and exposure time are used, the method provides quantitative information about the amount and affinity of neurotransmitter receptors in brain sections. This was established by comparisons of densitometric readings with parallel measurements made by scintillation counting of sections.

Absorptiometry, Photon↗
PubMed1982

Serotonin receptor modulation by estrogen in discrete brain nuclei.

The effect of estradiol on serotonin (5HT1) receptors of ovariectomized female rats was studied in discrete brain nuclei by a micro-binding assay and quantitative autoradiography. The two methods show similar distribution of the 5HT1 receptor and estradiol significantly increases the density of receptors in the preoptic area, anterior hypothalamus, lateral septum and arcuate-median eminence. The increase in 5HT1 receptors in these particular nuclei may be related to estrogen control of ovulation and/or other estrogen-mediated central phenomena.

Animals↗