Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01185 (vasopressin)
 23,126 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

When extracerebral dopa decarboxylase is inhibited by carbidopa, L-dopa lowers plasma renin activity (PRA). The present study was designed to determine whether this suppression of PRA is mediated by the sympathetic nerves, and to identify the peripheral adrenergic receptor types involved. All experiments were performed in pentobarbital-anesthetized dogs in which changes in renal perfusion pressure were minimized by means of a suprarenal aortic clamp. Neither alpha adrenoreceptor blockage with phenoxybenzamine nor beta adrenoreceptor blockade with propranolol was by itself sufficient to block the suppression of PRA by L-dopa with carbidopa. However, combined alpha and beta adrenoreceptor blockade lowered PRA and completely prevented any further suppression of PRA by L-dopa with carbidopa. It was also observed that phenoxybenzamine decreased PRA by 48% when administered to propranolol-treated animals. Taken together, these data indicate that L-dopa with carbidopa suppresses PRA by decreasing sympathetic nerve stimulation of both alpha and beta adrenoreceptors. Plasma vasopressin concnetration was significantly decreased by L-dopa with carbidopa both in the control group and in animals with combined alpha and beta adrenoreceptor blockade. Because plasma vasopressin levels decreased after L-dopa, vasopressin is unlikely to play a causative role in the suppression of PRA.
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PMID:Role of peripheral adrenoreceptors and vasopressin in the suppression of plasma renin activity by L-dopa in carbidopa-treated dogs. 48 Jan 87

The experiments were performed in rats anaesthetized with alpha-chloralose and urethane. Intracerebroventricular administration of hypertonic saline (icv. HS) resulted in an increase in renal plasma flow rate, glomerular filtration rate, urine flow rate, urinary sodium excretion, urinary potassium excretion, and osmolar clearance, and a decrease in free water clearance. These responses were abolished in hypophysectomized rats, but were not significantly affected by intravenous injection of vasopressin (VP) receptor (V1 and V2) antagonist. The urinary dopamine (DA) excretion did not change significantly after icv. HS. Moreover, administration of benserazide, an inhibitor of the enzyme L-aromatic amino acid decarboxylase that converts L-dopa to DA, did not attenuate the diuresis and natriuresis induced by icv. HS. These results suggest that the renal responses upon stimulation of the brain osmoreceptor are dependent on the integrity of the hypophysis, while the VP and DA are not essential to these renal responses. The hypophysial factors responsible for the icv. HS-induced renal responses remain to be explored.
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PMID:[Role of the hypophysis in the renal responses upon stimulation of the brain osmoreceptor]. 145 53

The colchicine-induced accumulation of vasopressin (AVP) and oxytocin (OXT) has recently been applied to estimate the synthesis and turnover rates for these neuropeptides in whole rat hypothalamus. In the present studies, this pharmacologic procedure has been examined as a potential method for estimating hypothalamic somatostatin (SRIF) synthesis rate, and evaluated further for its utility in estimating nonapeptide synthesis in individual hypothalamic nuclei. Adult male rats received a single injection of colchicine (8 micrograms) into the third ventricle under pentobarbital anesthesia. Twenty-four hr later, immunoreactive (IR) levels of AVP and OXT increased considerably, as previously noted. Hypothalamic IR-SRIF levels, however, were unaffected. The absolute increases in IR-AVP and IR-OXT were greatest in the supraoptic nucleus (SON), with smaller increments in the para/periventricular hypothalamus (PVH) and the median eminence (ME). IR-SRIF levels showed no changes in the PVH or the ME. As a test, the method was applied to the detection of changes in AVP synthesis in diabetic rats. The colchicine procedure reported increases in AVP synthesis in both the SON and PVH in diabetic animals, a result compatible with that obtained previously for whole hypothalamus using radiolabeled procedures. Together, the results indicate that the colchicine procedure is useful in detecting changes in the syntheses of some (AVP and OXT) but not all (SRIF) neuropeptides, and that when applicable, the method is sufficiently sensitive to detect changes in small hypothalamic regions. The method may prove useful in estimating changes in peptide synthesis analogous to that used for serotonin and dopamine; e.g., 5-hydroxytryptophan and dopa accumulation following inhibition of aromatic L-amino acid decarboxylase.
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PMID:Colchicine-induced increases in immunoreactive neuropeptide levels in hypothalamus: use as an index of biosynthesis. 167 40

The potential role of adrenaline, both circulating and in the central nervous system, in the maintenance of high blood pressure was examined in stroke-prone spontaneously hypertensive rats (SHRSP). alpha-Monofluoromethyldopa, a long-lasting inhibitor of dopa decarboxylase, was used to induce rapid depletion of central and peripheral catecholamine stores. Subsequent inhibition of phenylethanolamine-N-methyltransferase (PNMT) allowed the gradual restoration of dopamine and noradrenaline but not adrenaline, resulting in a greater relative depletion of adrenaline. Adrenaline was almost totally depleted in the circulation and peripheral tissues. The resting level of blood pressure, however, was unaffected, excepting after administration of a vasopressin (AVP) antagonist. Moreover, there was no reduction in the magnitude of acute pressor responses to electrical stimulation of the rostral ventrolateral medulla oblongata (C1 area), despite extensive loss of adrenaline from the brainstem and spinal cord. The results suggest that adrenaline contributes to the resting level of blood pressure but that its loss can be offset by the pressor activity of AVP. Thus neither central nor peripheral adrenaline stores appear to be essential for the maintenance of hypertension or for centrally-evoked vasoconstriction in adult SHRSP.
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PMID:Effects of depleting central and peripheral adrenaline stores on blood pressure in stroke-prone spontaneously hypertensive rats. 194 21

Elevation of brain catecholamine levels by systemic administration of L-dopa in dogs pretreated with the dopa decarboxylase inhibitor carbidopa inhibits the secretion of vasopressin and adrenocorticotropic hormone (ACTH) and decreases arterial blood pressure. The aim of the present study was to determine whether the inhibition of vasopressin secretion is mediated by dopamine or norepinephrine, both of which have been implicated in the control of vasopressin secretion, and whether the decrease in vasopressin secretion contributes to the suppression of ACTH secretion and fall in blood pressure produced by L-dopa. This was accomplished by comparing the effects of dopamine and alpha-adrenergic receptor antagonists on vasopressin, ACTH, and blood pressure responses to L-dopa. The effect of a specific antagonist of the vasoconstrictor action of vasopressin also was studied. Injection of L-dopa (20 mg/kg i.v.) in dogs pretreated with carbidopa (20 mg/kg i.v.) caused reductions in plasma vasopressin concentration (from 16.0 +/- 4.8 to 3.8 +/- 0.9 pg/ml; p less than 0.05), plasma ACTH concentration (from 96.0 +/- 20.4 to 49.2 +/- 10.0 pg/ml; p less than 0.05), and mean arterial pressure (from 121 +/- 6 to 78 +/- 5 mm Hg; p less than 0.05). Pretreatment with pimozide (1 mg/kg i.p.) completely blocked the inhibition of vasopressin secretion by L-dopa but failed to block the suppression of ACTH secretion (57.6 +/- 11.8 to 34.0 +/- 5.1 pg/ml; p less than 0.05) or the decrease in mean arterial pressure (126 +/- 5 to 93 +/- 7 mm Hg; p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Role of dopamine in the inhibition of vasopressin secretion by L-dopa in carbidopa-treated dogs. 287 46

We demonstrated the coexistence of aromatic L-amino acid decarboxylase (AADC) and arginine-vasopressin in neurons of the hypothalamic suprachiasmatic nucleus of Sprague-Dawley rats. Neurons that lacked monoamines but expressed immunoreactivity to the enzyme AADC occupied the rostral and caudal poles of the suprachiasmatic nucleus and mediodorsal and dorsolateral positions along the entire extent of the nucleus. AADC was also localized in similar neurons of the suprachiasmatic nucleus of rats from other strains including the homozygous Brattleboro rat.
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PMID:Aromatic L-amino acid decarboxylase in the rat brain: coexistence with vasopressin in small neurons of the suprachiasmatic nucleus. 662 18

We investigated the distribution, diurnal variation, and time of expression of aromatic L-amino acid decarboxylase (AADC), a second-step enzyme of the monoamine synthetic pathway, in the rat suprachiasmatic nucleus (SCN), by immunocytochemistry and in situ hybridization. AADC immunoreactive and mRNA expressing cells were observed in the dorsomedial and dorsolateral portions of the SCN. Double labeling immunofluorescence demonstrated that about 70% of AADC neuron in the dorsomedial portion contained vasopressin immunoreactivity. AADC mRNA expression in the SCN showed day-night variation, with higher signals in the daytime than at night. Developmental study demonstrated that AADC immunoreactivity and mRNA in the SCN were expressed at embryonic day 18, the onset time for fetal circadian rhythm. These findings suggest that AADC neurons in the SCN may play some role in the generation and entrainment of circadian rhythm.
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PMID:[Expression of aromatic L-amino acid decarboxylase in the rat suprachiasmatic nucleus--immunocytochemistry and in situ hybridization study]. 794 36

Small-cell carcinoma of the lung (SCCL) is a neuroendocrine tumor characterized by having the capacity to produce and secrete a number of small neuropeptides. These peptides serve the tumor as autocrine growth factors. SCCL is known to undergo a process of dedifferentiation to a variant (drug-resistant) form, and this process is associated with loss of marker enzymes such as neuron-specific enolase (NSE) and dopa decarboxylase (DDC). The current study was designed to discover if variant SCCL, represented by cell line NCI H82, retains some capacity to generate active neuropeptides (like vasopressin) from their precursors by continuing to express the three key classes of enzymes necessary for such conversions, namely prohormone convertases (PCs), carboxypeptidases (CPs), and peptidylglycine a-amidating monooxygenase (PAM). RT-PCR for mRNAs representing PC1, PC2, CPE, and PAM was performed on total RNA extracted from NCI H82. The primers selected for PCR and partial sequencing were synthetic 20, 21, 22, and 24 oligomers designed to yield products of 533, 880, 405, and 560 base pairs (bp) for PC1, PC2, CPE, and PAM, respectively. For the conditions used, we were able to demonstrate products for all four enzymes. Each of the four products generated were of the expected size. Cloning and sequencing of these products revealed that each had a structure identical to that published for the human form of the respective enzyme. Western analysis with antibodies against PC1, PC2, CPE, and PAM, provided evidence that mRNAs for the four enzymes are translated into proteins that could represent functional forms. Our findings therefore demonstrate that key enzymes involved in the generation of active neuropeptides, unlike the marker enzymes NSE and DDC, continue to be expressed by variant SCCL.
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PMID:Key peptide processing enzymes are expressed by a variant form of small-cell carcinoma of the lung. 988 81

By using degenerate primers designed from glutamate decarboxylase (GAD) sequences of mammals, Xenopus and Drosophila, a 270-bp cDNA fragment was cloned by reverse transcriptase-polymerase chain reaction (RT-PCR) from cerebellum total RNA of rainbow trout. This partial cDNA shows 90% identity with mammalian GAD 65 and presents the Asn-Pro-His-Lys (NPHK) sequence corresponding to the pyridoxal-binding region of porcine DOPA decarboxylase or mammalian GAD. The distribution of GAD 65 mRNA-expressing neurons in the forebrain of the trout was studied by in situ hybridization using either digoxigenin- or 35S-labeled probes. The results demonstrate that gamma-amino butyric acid (GABA) neurons are widely distributed throughout the forebrain, with a high density in the periventricular regions. In this study, we report their precise distribution in the telencephalon and diencephalon. GAD mRNA-expressing cells were particularly abundant in the preoptic region and the mediobasal hypothalamus, two major neuroendocrine and estrogen-sensitive regions in fish. The presence of GAD mRNA-expressing neurons was observed in visually related structures such as the suprachiasmatic nucleus, the pretectal region, and the thalamus. Immunohistochemistry with antibodies directed against mouse GAD failed to demonstrate the presence of immunoreactive cell bodies, but showed a very high concentration of GAD-immunoreactive fibers in many brain regions, notably in the preoptic area, hypothalamus, and neurohypophyseal digitations of the pituitary, in particular in the proximal pars distalis. These results indicate that GABA neurons are ideally placed to modulate neuroendocrine activities at the hypothalamic and pituitary levels and to participate in the processing of sensorial information.
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PMID:Distribution of glutamic acid decarboxylase mRNA in the forebrain of the rainbow trout as studied by in situ hybridization. 1041 33

Hypothalamic magnocellular neurons constitute a good model of neurochemical plasticity, because a single neuron can express various combinations of neuropeptides and enzymes under different physiological conditions. Tyrosine hydroxylase has been shown to occur ectopically in various non-catecholaminergic neurons. We investigated the expression of tyrosine hydroxylase and its possible role in the magnocellular neurons of the supraoptic and paraventricular nuclei in salt-loaded and lactating rats, using in situ hybridization and immunohistochemistry, alone or combined, in light and electron microscopy. Our results demonstrated that almost 25% of the magnocellular neurons in the supraoptic nucleus and 15% in the paraventricular nucleus expressed tyrosine hydroxylase in salt-loaded rats, and 10% in the supraoptic nucleus of two-day lactating rats. Double labelling showed that this tyrosine hydroxylase was essentially synthesized in magnocellular neurons expressing vasopressin. The ultrastructural localization of tyrosine hydroxylase was less homogeneous in the cytoplasm of magnocellular neurons than in periventricular neurons. In lactating and salt-loaded rats, magnocellular neurons were devoid of the catecholamine biosynthesis markers aromatic L-amino acid decarboxylase, L-3,4 dihydroxyphenylalanine, dopamine and GTP-cyclohydrolase I. Tyrosine hydroxylase expression did not increase after rats were injected with reserpine. Our results indicate that the phenotype of the magnocellular neurons expressing tyrosine hydroxylase in lactating and salt-loaded rats is non-catecholaminergic, and suggest that this tyrosine hydroxylase might be involved in osmoregulation.
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PMID:Ectopic expression of non-catecholaminergic tyrosine hydroxylase in rat hypothalamic magnocellular neurons. 1061 5


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