A spinal GABAergic mechanism is necessary for bladder inhibition by pudendal afferent stimulation

作者：McGee Meredith J; Danziger Zachary C; Bamford Jeremy A; Grill Warren M^*

来源：American Journal of Physiology - Renal Fluid and Electrolyte Physiology, 2014, 307(8): F921-F930.

DOI：10.1152/ajprenal.00330.2014

• electrical stimulation
• bladder inhibition
• pudendal nerve
• dorsal nerve of the penis
• GABA
• picrotoxin

Electrical stimulation of pudendal afferents can inhibit bladder contractions and increase bladder capacity. Recent results suggest that stimulation-evoked bladder inhibition is mediated by a mechanism other than activation of sympathetic bladder efferents in the hypogastric nerve, generating alpha-adrenergic receptor-mediated inhibition at the vesical ganglia and/or beta-adrenergic receptor-mediated direct inhibition of the detrusor muscle. We investigated several inhibitory neurotransmitters that may instead be necessary for stimulation-evoked inhibition and found that intravenous picrotoxin, a noncompetitive GABA(A) antagonist, significantly and reversibly blocked pudendal afferent stimulation-evoked inhibition of bladder contractions in a dose-dependent manner. Similarly, intravenous picrotoxin also blocked pudendal afferent stimulation-evoked inhibition of nociceptive bladder contractions evoked by acetic acid infusion. Furthermore, intrathecal administration of picrotoxin at the lumbosacral spinal cord also blocked bladder inhibition by pudendal afferent stimulation. On the other hand, glycinergic, adrenergic, or opioidergic mechanisms were not necessary for bladder inhibition evoked by pudendal afferent stimulation. These results identify a lumbosacral spinal GABAergic mechanism of bladder inhibition evoked by pudendal afferent stimulation.

• 出版日期2014-10-15