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Inhibitory Role of Gamma‐amino‐butyric Acid in the Rabbit Urinary Bladder
Author(s) -
CHEN T. F.,
DOYLE P. T.,
FERGUSON D. R.
Publication year - 1992
Publication title -
british journal of urology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.773
H-Index - 148
eISSN - 1464-410X
pISSN - 0007-1331
DOI - 10.1111/j.1464-410x.1992.tb15449.x
Subject(s) - bicuculline , carbachol , inhibitory postsynaptic potential , agonist , chemistry , medicine , endocrinology , gamma aminobutyric acid , gabaa receptor , receptor , detrusor muscle , gaba receptor antagonist , neurotransmitter , stimulation , muscle contraction , urinary bladder , pharmacology , biology , biochemistry
Summary— Gamma‐amino‐butyric acid (GABA) is an established inhibitory neurotransmitter in the central nervous system (CNS) and it has also been identified in the bladder. We have investigated in the rabbit the effect of GABA on detrusor activity. Rabbit detrusor muscle strips were made to contract by electrical stimulation of their autonomic nerves or by the addition of carbachol. The addition of GABA caused substantial inhibition of muscle contraction. GABA acts on 2 classes of receptors‐GABA A and GABA B . The inhibition was mediated via the GABA B receptors as its effect was mimicked by baclofen (a GABA B agonist) and inhibited by 2‐hydroxysaclofen (a GABA B receptor antagonist). Inhibition was not prevented by bicuculline (a GABA A receptor antagonist). This inhibition may be due to a direct muscle effect since the inhibition, which occurred with carbachol‐induced contraction, was not abolished by the addition of tetrodotoxin. GABA, acting via the GABA B receptor, produces substantial inhibition of muscle contraction in the rabbit uinary bladder. This raises the possibility of using GABA B analogues in the treatment of detrusor instability.