Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Microinjection of the inhibitory neurotransmitter gamma-aminobutyric acid B-subtype receptor agonist baclofen into the nucleus tractus solitarius increases arterial blood pressure and sympathetic nerve discharge. The baclofen-induced pressor response is enhanced in chronic hypertension. We hypothesized that a postsynaptic mechanism contributes to the enhanced responses to baclofen in hypertension. We investigated the postsynaptic effect of baclofen on second-order baroreceptor neurons, identified by 1,1'-dilinoleyl-3,3,3',3'-tetra-methylindocarbocyanine, 4-chlorobenzenesulphonate labeling of the aortic nerve, in nucleus tractus solitarius slices from sham-operated normotensive and unilateral nephrectomized, renal-wrap hypertensive rats. After 4 weeks, arterial blood pressure was 153+/-7 mm Hg in hypertensive rats (n=9) and 93+/-3 mm Hg in normotensive rats (n=8; P<0.05). There was no difference in resting membrane potential (54.5+/-0.7 versus 53.3+/-0.6 mV) or input resistance (1.07+/-0.11 versus 1.03+/-0.11 GOmega) between hypertensive and normotensive neurons (both n=18). Baclofen induced a net outward current in nucleus tractus solitarius neurons in the presence of 1 micromol/L tetrodotoxin. The EC50 of the baclofen effect was greater in normotensive cells (9.1+/-3.2 micromol/L; n=5) than hypertensive cells (3.0+/-0.5 micromol/L; n=7; P<0.05), and baclofen (10 micromol/L) induced a greater decrease in input resistance in hypertensive cells (61+/-2%; n=6) than in normotensive cells (45+/-4%; n=9; P<0.05). Both potassium and calcium channels were involved in the baclofen-evoked whole-cell current. The results suggest an enhanced postsynaptic response to activation of inhibitory neurotransmitter gamma-aminobutyric acid B-subtype receptors in second-order baroreceptor neurons in the nucleus tractus solitarius in renal-wrap hypertensive rats. This enhanced inhibition could alter baroreflex function in chronic hypertension.
Hypertension 2007 Mar
PMID:Chronic hypertension enhances the postsynaptic effect of baclofen in the nucleus tractus solitarius. 1714 79

Opioids evoke respiratory depression, bradycardia, and reduced respiratory sinus arrhythmia, whereas serotonin (5-HT) agonists stimulate respiration and cardiorespiratory interactions. This study tested whether serotonin agonists can prevent the inhibitory effects of opioids on cardiorespiratory function. Spontaneous and rhythmic inspiratory-related activity and gamma-aminobutyric acid (GABA) neurotransmission to premotor parasympathetic cardioinhibitory neurons in the nucleus ambiguus were recorded simultaneously in an in vitro thick slice preparation. The mu-opioid agonist fentanyl inhibited respiratory frequency. The 5-hydroxytryptamine 1A/7 receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin increased respiratory frequency by itself and also prevented the fentanyl-induced respiratory depression. The 5-hydroxytryptamine 4alpha agonist BIMU-8 did not by itself change inspiratory activity but prevented the mu-opioid-mediated respiratory depression. Both spontaneous and inspiratory-evoked GABAergic neurotransmission to cardiac vagal neurons were inhibited by fentanyl. 8-Hydroxy-2-(di-n-propylamino)tetralin inhibited spontaneous but not inspiratory-evoked GABAergic activity to parasympathetic cardiac neurons. However, 8-hydroxy-2-(di-n-propylamino)tetralin differentially altered the opioid-mediated depression of inspiratory-evoked GABAergic activity but did not change the opioid-induced reduction in spontaneous GABAergic neurotransmission. In contrast, BIMU-8 did not alter GABAergic neurotransmission to cardiac vagal neurons by itself but prevented the fentanyl depression of both spontaneous and inspiratory-elicited GABAergic neurotransmission to cardiac vagal neurons. In the presence of tetrodotoxin, the inhibition of GABAergic inhibitory postsynaptic currents with fentanyl is prevented by coapplication of BIMU-8, indicating that BIMU-8 acts at presynaptic GABAergic terminals to prevent fentanyl-induced depression. These results suggest that activation of 5-hydroxytryptamine receptors, particularly 5-hydroxytryptamine 4alpha agonists, may be a useful therapeutic approach in preventing opioid-evoked cardiorespiratory depression.
Hypertension 2007 Aug
PMID:5-Hydroxytryptamine 1A/7 and 4alpha receptors differentially prevent opioid-induced inhibition of brain stem cardiorespiratory function. 1757 56

Increased dietary salt exaggerates arterial blood pressure (ABP) responses evoked from the rostral ventrolateral medulla (RVLM). The present study determined whether these enhanced pressor responses were directly attributable to a greater increase in sympathetic nerve activity (SNA) and whether these enhanced responses were balanced by a greater responsiveness of RVLM neurons to inhibitory input. Male Sprague-Dawley rats were fed normal chow and given access to either water or a 1% NaCl solution for 14 days. Injection of l-glutamate (0.03, 0.1, 1.0, and 3.0 nmol) into the RVLM produced a significantly greater increase in renal SNA, splanchnic SNA, and ABP in rats drinking 1% NaCl versus water. Conversely, injection of the inhibitory amino acid gamma-aminobutyric acid (0.1, 1.0, and 10 nmol) into the RVLM produced significantly greater decreases in renal SNA, splanchnic SNA, and ABP of rats drinking 1% NaCl versus water. These enhanced SNA and ABP responses to l-glutamate and gamma-aminobutyric acid were not observed in rats drinking 1% NaCl for 1 or 7 days but were present in rats drinking 1% NaCl for 21 days. Moreover, the dietary salt-induced enhancement of both sympathoexcitatory and sympathoinhibitory responses from the RVLM persisted after the 1% NaCl solution was replaced with water for 1, but not 7, days. These findings indicate that the potentiated ABP responses observed previously are mediated by parallel changes in SNA, and these responses depend on a slowly developing and reversible form of neuronal plasticity.
Hypertension 2007 Aug
PMID:Increased dietary salt enhances sympathoexcitatory and sympathoinhibitory responses from the rostral ventrolateral medulla. 1759 69

Intrathecal baclofen (ITB) withdrawal is a well-recognized complication when drug delivery is disrupted for any reason. ITB withdrawal varies widely in its severity and poses the very real possibility of death if not promptly managed. Cases of withdrawal lasting greater than 1 or 2 weeks, however, are sparse. We report the case of an 11-year-old girl with spastic quadriplegic cerebral palsy who developed an infected pump and subsequent meningitis, prompting the removal of her pump and catheter. She subsequently developed a severe, prolonged baclofen withdrawal syndrome marked by increased spasticity, agitation, hypertension, and tachycardia that lasted nearly 2 months, requiring intensive care and continuous intravenous sedation with benzodiazepines and opiates. Her pump was eventually replaced on hospital day 56 and within 24 hours her symptoms dramatically improved. She was eventually weaned off sedating medications and returned to baseline functional status. Typical management of baclofen withdrawal is reviewed. To date, the literature has not discussed the potential role for opiates in managing baclofen withdrawal, yet a growing body of literature is examining the interplay between opiates and gamma-aminobutyric acid B pathways. A potential role for opiates in managing severe baclofen withdrawal is proposed.
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PMID:Prolonged, severe intrathecal baclofen withdrawal syndrome: a case report. 1796 89

Tiagabine is an anticonvulsant acting by selective inhibition of neuronal and glial gamma-aminobutyric acid uptake, resulting in increased gamma-aminobutyric acid-mediated inhibition in the brain. Few reports in the literature describe the clinical course of severe tiagabine intoxication. A 44-year-old woman presented after deliberate self-poisoning with 100 tiagabine 15 mg tablets (1,500 mg; 25 mg/kg). Serum tiagabine level was 4,600 microg/L (1,725 mmol/L) at presentation, 20 times levels associated with therapeutic dosing. Intoxication was manifested by profuse vomiting, coma, myoclonus, generalized rigidity, bradycardia, hypertension, hypersalivation and generalized piloerection within 2 h of ingestion. The patient was intubated and management was supportive. Coma lasted until 10 h post-ingestion, but recovery was complicated by severe agitated delirium lasting 12 h. The patient recovered fully within 26 h of ingestion. Tiagabine deliberate self-poisoning was associated with the rapid onset of coma and an unusual toxidrome. Recovery, although complicated by agitated delirium, was complete within 26 h.
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PMID:Deliberate self-poisoning with tiagabine: an unusual toxidrome. 1878 11

Cushing's syndrome results from lengthy and inappropriate exposure to excessive concentrations of either endogenous or exogenous glucocorticoids. This case report describes a patient with a novel type of Cushing's syndrome due to the use of party drugs. A 35-year-old woman had gained 8 kg body weight in 5 months and complained of anxiety. She showed a Cushing-like appearance and mild hypertension (blood pressure, BP 150/95 mmHg). She reported daily use of increasing doses of gamma-hydroxybutyric acid (GHB), a popular party drug. ACTH plasma levels were in the upper normal range (41 ng/l), with normal plasma cortisol (0.36 micromol/l). She showed an abnormal overnight 1 mg dexamethasone suppression test (cortisol 0.38 micromol/l). The urinary excretion of free cortisol in 24 h was also increased (0.47 micromol/24 h). CT scanning of the abdomen showed normal adrenals. After stopping GHB intake she lost 7 kg body weight and her BP normalized (BP 135/80 mmHg). GHB is a popular party drug in the Netherlands, but it is also used as a narcotic and for the treatment of narcolepsy. We hypothesize that GHB may bind to the pituitary gland gamma-aminobutyric acid-B receptors leading to ACTH overproduction.
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PMID:A 'smart' type of Cushing's syndrome. 1805 86

Chloride channels represent a relatively under-explored target class for drug discovery as elucidation of their identity and physiological roles has lagged behind that of many other drug targets. Chloride channels are involved in a wide range of biological functions, including epithelial fluid secretion, cell-volume regulation, neuroexcitation, smooth-muscle contraction and acidification of intracellular organelles. Mutations in several chloride channels cause human diseases, including cystic fibrosis, macular degeneration, myotonia, kidney stones, renal salt wasting and hyperekplexia. Chloride-channel modulators have potential applications in the treatment of some of these disorders, as well as in secretory diarrhoeas, polycystic kidney disease, osteoporosis and hypertension. Modulators of GABA(A) (gamma-aminobutyric acid A) receptor chloride channels are in clinical use and several small-molecule chloride-channel modulators are in preclinical development and clinical trials. Here, we discuss the broad opportunities that remain in chloride-channel-based drug discovery.
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PMID:Chloride channels as drug targets. 1915 58

Gamma-aminobutyric acid (GABA) is a four-carbon amino acid that is commonly present in living organisms and functions as a major inhibitory neurotransmitter in mammals. It is understood to have a potentially anti-hypertensive effect in mammals. GABA is synthesized from glutamate by glutamate decarboxylase (GAD). In plants, GAD is regulated via its calmodulin-binding domain (CaMBD) by Ca(2+)/CaM. We have previously reported that a C-terminal truncated version of one of the five rice GAD isoforms, GAD2DeltaC, revealed higher enzymatic activity in vitro and that its over-expression resulted in exceptionally high GABA accumulation (Akama and Takaiwa, J Exp Bot 58:2699-2607, 2007). In this study, GAD2DeltaC, under the control of the rice glutelin promoter (GluB-1), was introduced into rice cells via Agrobacterium-mediated transformation to produce transgenic rice lines. Analysis of the free amino acid content of rice grains revealed up to about a 30-fold higher level of GABA than in non-transformed rice grains. There were also very high levels of various free protein amino acids in the seeds. GABA-enriched rice grains were milled to a fine powder for oral administration to spontaneously hypertensive rats (SHRs) and normotensive Wistar-Kyoto rats (WKYs). Six weeks of administration showed that transgenic rice brings about a 20 mmHg decrease in blood pressure in two different kinds of SHRs, while there was no significant hypotensive effect in WKYs. These results suggest an alternative way to control and/or cure hypertension in humans with GABA-enriched rice as part of a common daily diet.
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PMID:Seed-specific expression of truncated OsGAD2 produces GABA-enriched rice grains that influence a decrease in blood pressure in spontaneously hypertensive rats. 1943 9

Increased dietary salt enhances sympathoexcitatory and sympathoinhibitory responses evoked from the rostral ventrolateral medulla (RVLM). The purpose of the present study was to determine whether neurons of the forebrain lamina terminalis (LT) mediated these changes in the RVLM. Male Sprague-Dawley rats with and without LT lesions were fed normal chow and given access to water or 0.9% NaCl for 14 to 15 days. Unilateral injection of l-glutamate into the RVLM produced significantly larger increases in renal sympathetic nerve activity and arterial blood pressure of sham rats ingesting 0.9% NaCl versus water. However, these differences were not observed between ventral LT-lesioned rats drinking 0.9% NaCl versus water. Similar findings were observed when angiotensin II or gamma-aminobutyric acid was injected into the RVLM. Interestingly, a subset of animals drinking 0.9% but with damage restricted to the organum vasculosum of the lamina terminalis did not show enhanced responses to l-glutamate or gamma-aminobutyric acid. In marked contrast, RVLM injection of l-glutamate or gamma-aminobutyric acid produced exaggerated sympathetic nerve activity and arterial blood pressure responses in animals drinking 0.9% NaCl versus water after an acute ventral LT lesion or chronic lesion of the subfornical organ. Additional experiments demonstrated that plasma sodium concentration and osmolality were increased at night in rats ingesting 0.9% NaCl. These findings suggest that neurons of the ventral LT mediate the ability of increased dietary salt to enhance the responsiveness of RVLM sympathetic neurons.
Hypertension 2009 Aug
PMID:Ventral lamina terminalis mediates enhanced cardiovascular responses of rostral ventrolateral medulla neurons during increased dietary salt. 1950 2

The anti-hypertensive effect of GABA-rich Chlorella was studied after oral administration for 12 weeks in the subjects with high-normal blood pressure and borderline hypertension in the placebo-controlled, double-blind manner in order to investigate if GABA-rich Chlorella, a dietary supplement, is useful in control of blood pressure. Eighty subjects with Systolic blood pressure (SBP) 130-159 mmHg or diastolic blood pressure (DBP) 85-99 mmHg (40 subjects/group) took the blinded substance of GABA-rich Chlorella (20 mg as gamma-aminobutyric acid) or placebo twice daily for 12 weeks, and had follow-up observation for an additional 4 weeks. Systolic blood pressure in the subjects given GABA-rich Chlorella significantly decreased compared with placebo (p < 0.01). Diastolic blood pressure had the tendency to decrease after intake of GABA-rich Chlorella. Neither adverse events nor abnormal laboratory findings were reported throughout the study period. Reduction of SBP in the subjects with borderline hypertension was higher than those in the subjects with high-normal blood pressure. These results suggest that GABA-rich Chlorella significantly decreased high-normal blood pressure and borderline hypertension, and is a beneficial dietary supplement for prevention of the development of hypertension.
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PMID:Anti-hypertensive effect of gamma-aminobutyric acid (GABA)-rich Chlorella on high-normal blood pressure and borderline hypertension in placebo-controlled double blind study. 1981 62


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