Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.26.9 (ribonuclease)
 6,589 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The distribution of the mRNAs encoding the dopamine D1, D2 and D5 receptors was determined in brain tissues obtained from intact female rhesus monkeys, using a ribonuclease protection assay. Tissue blocks from the frontal cortex, striatum, thalamus, hippocampus and substantia nigra were dissected and total RNA was extracted. Dopamine D2 and D5 receptor DNA fragments were generated from rhesus monkey genomic DNA using polymerase chain reaction. To generate dopamine receptor subtype-specific cRNA probes, DNA fragments corresponding to the carboxy terminus of the rhesus monkey D1 and D2 receptor genes and to the putative transmembrane domain regions (IV-VI) of the D5 receptor gene, were subcloned into the pGEM3Z/4Z vectors. Expression of D1 receptor mRNA exhibited significant regional differences: striatum > > > cerebral cortex > or = hippocampus > or = lateral thalamus. D1 receptor mRNA was found in low quantities in the medial thalamus, but was not consistently expressed in the substantia nigra area. In contrast, D2 receptor mRNA was detected in all regions that were studied: striatum > > > substantia nigra > > hippocampus > or = cerebral cortex > or = medial thalamus > or = lateral thalamus. D5 receptor mRNA was also expressed in all regions, with highest levels in the cerebral cortex, striatum and lateral thalamus, and moderate levels in the substantia nigra, medial thalamus and the hippocampus. The D5 receptor mRNA appears to be widely distributed in the monkey brain. Most interesting is the expression of D5 receptor mRNA in tissues of the substantia nigra area.
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PMID:Distribution of dopamine D1, D2, and D5 receptor mRNAs in the monkey brain: ribonuclease protection assay analysis. 747 36

Dopamine receptors have been localized to several tissues outside the central nervous system including the kidney and mesenteric vessels. To determine if there are dopamine1 receptors within the small intestine, homogenates of the antimesenteric halves of the entire jejunum and ileum of adult rats were prepared and competitive inhibition studies and Scatchard analysis were performed at room temperature using 125I-SCH 23982 and SCH 23390. The specific binding of 125I-SCH 23982 to the intestinal tissue homogenates was rapid, saturable with ligand concentration, and reversible. Analysis of the Scatchard plots revealed a single class of receptors with an apparent dissociation constant of 10.77 +/- 2.32 nM and maximum receptor density of 1.37 +/- 0.34 fmole/mg protein. Emulsion autoradiography performed using 125I-SCH 23982 on antimesenteric sections of the rat small intestine revealed that the dopamine1 receptors are located on cells at the base of the intestinal crypts. Two dopamine1 subtypes (D1A and D1B) have been identified by molecular biological techniques. Using a ribonuclease protection assay we found expression of the D1A receptor gene in the small intestinal tissue. These studies are the first to identify, characterize, and localize receptors for the endogenous catecholamine, dopamine, within the rat small intestine and to confirm the expression of the D1A receptor gene.
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PMID:Identification of dopamine1A receptors in the rat small intestine. 841 73

The effects of in utero cocaine exposure on the development of the mRNAs encoding the dopamine transporter (DAT) and the D1, D2 and D5 dopamine receptor subtypes were determined in fetal monkey brains at day 45 and day 60 of gestation. Pregnant monkeys were treated with cocaine 3 mg/kg or saline i.m., four times a day from day 18 of gestation until the pregnancy was terminated at day 45 or day 60. The fetal brains were dissected, and tissue RNA extracted and quantified using ribonuclease protection assay analysis. In day 45 fetal monkeys, dopamine D1 and D2 receptor subtype mRNAs and DAT mRNA were found in low quantities both in control and cocaine-treated subjects. In day 60 fetal monkeys, D1 receptor mRNA levels were highest in the frontal cortex/striatal area, and low to moderate quantities were found in diencephalic and mesencephalic fetal brain regions. Dopamine D2 receptor mRNA levels were highest in the frontal cortex/striatal area, diencephalon and the midbrain, moderate in the brainstem and low in the caudal temporal lobe and surrounding cortical areas. Dopamine D5 receptor mRNA was expressed in low quantities throughout the day 60 fetal monkey brain, whereas DAT mRNA was found in the midbrain only. In utero cocaine exposure caused a significant increase in dopamine D1, D2 and D5 receptor subtype mRNAs in the frontal cortex/striatal area of day 60 fetal monkeys. These results support the hypothesis that dopamine synthesis and release may be reduced in cocaine-treated fetuses, which results in dopamine receptor up-regulation.
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PMID:Effects of in utero cocaine exposure on the expression of mRNAS encoding the dopamine transporter and the D1, D2 and D5 dopamine receptor subtypes in fetal rhesus monkey. 892 87