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Gamma-aminobutyric Acid Receptor (gamma-aminobutyric + acid_receptor)

Distribution by Scientific Domains

Medical Sciences	75%

Selected Abstracts

Possible Contribution of Central Gamma-Aminobutyric Acid Receptors to Resting Vascular Tone in Freely Moving Rats

EXPERIMENTAL PHYSIOLOGY, Issue 5 2000
Yumi Takemoto
Previous studies have shown that central administration of GABA (gamma-aminobutyric acid), an inhibitory neurotransmitter, preferentially reduces hindquarters and carotid vascular resistances but not renal and coeliac vascular resistances in conscious rats. This study tested the hypothesis that these preferential actions of central GABA receptors are related to differences between vessels in resting autonomic vascular tone in freely moving rats. Rats were chronically implanted with intracisternal cannulas and/or electromagnetic probes to measure regional blood flows. In response to GABA administration, the changes in vascular resistance (arterial blood pressure/regional blood flow) of the hindquarters (n = 23) and carotid (n = 12) vascular beds were significantly and negatively correlated with basal vascular resistance. No such relationship was found for the renal (n = 21), coeliac (n = 13) and superior mesenteric (n = 23) vascular beds. This finding indicates that the responsiveness to GABA of brainstem pathways controlling the hindquarters and carotid vascular beds co-varies with resting resistance in hindquarters and carotid vessels. A similar analysis was performed, correlating the ongoing vascular resistance of each vessel with its response to ganglionic blockade by chlorisondamine. In this case, a significant negative correlation was also found for the hindquarters (n = 26) and carotid (n = 15) vascular beds, but not for the coeliac (n = 17) or superior mesenteric (n = 19) vessels. Together, these findings suggest that central GABA receptors accessible from the cisterna magna preferentially affect two vascular beds which, in the freely moving rat, show resting autonomic vascular tone. [source]

Further evidence for an association between the gamma-aminobutyric acid receptor A, subunit 4 genes on chromosome 4 and Fagerström Test for Nicotine Dependence

ADDICTION, Issue 3 2009
Arpana Agrawal
ABSTRACT Aims A previous association analysis identified polymorphisms in gamma-aminobutyric acid receptor A, subunit 4 (GABRA4) and GABRA2 to be associated with nicotine dependence, as assessed by a score of 4 or more on the Fagerström Test for Nicotine Dependence (FTND). In the present report, we extend the previous study by expanding our genotyping efforts significantly for these two genes. Design In 1049 cases (FTND of 4 or more) and 872 controls (smokers with FTND of 0) from the United States and Australia, we examine the association between 23 GABRA4 and 39 GABRA2 recently genotyped single nucleotide polymorphisms (SNPs) and nicotine dependence using logistic regression-based association analyses using the genomic analysis package PLINK. Results Two and 18 additional SNPs in GABRA4 and GABRA2, respectively, were associated with nicotine dependence. The SNPs identified in GABRA4 (P -value = 0.002) were restricted to introns 1 and 2, exon 1 and the 5, end of the gene, while those in GABRA2 localized to the 3, end of the gene and spanned introns 9,3, and were in moderate to high linkage disequilibrium (as measured by r2) with each other and with previously studied polymorphisms. Conclusion Our findings demonstrate consistently the role of GABRA4 and GABRA2 in nicotine dependence. However, further research is needed to identify the biological influence of these intronic variations and to isolate functionally relevant polymorphisms neighboring them. [source]

Endogenous neurosteroid synthesis modulates seizure frequency

ANNALS OF NEUROLOGY, Issue 5 2010
Courtney Lawrence
Inhibitory neurosteroids, molecules generated in glia from circulating steroid hormones and de novo from cholesterol, keep seizures in check in epileptic animals. They can enhance inhibitory transmission mediated by gamma-aminobutyric acid receptors and have anticonvulsant action. ANN NEUROL 2010;67:689,693 [source]