Excitatory GABAA receptor in autonomic pelvic ganglion neurons innervating bladder.
Major pelvic ganglia (MPG) are relay centers for autonomic reflexes such as micturition and penile erection. MPG innervate the urogenital system, including bladder. γ-Aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the mammalian central nervous system, and may also play an important role in some peripheral autonomic ganglia, including MPG. However, the electrophysiological properties and function of GABAA receptor in MPG neurons innervating bladder remain unknown. This study examined the electrophysiological properties and functional roles of GABAA receptors in bladder-innervating neurons identified by retrograde Dil tracing. Neurons innervating bladder showed previously established parasympathetic properties, including small membrane capacitance, lack of T-type Ca(2+) channel expression, and tyrosine-hydroxylase immunoreactivity. GABAA receptors were functionally expressed in bladder innervating neurons, but GABAC receptors were not. GABA elicited strong depolarization followed by increase of intracellular Ca(2+) in neurons innervating bladder, supporting the hypothesis GABA may play an important role in bladder function. These results provide useful information about the autonomic function of bladder in physiological and pathological conditions.
Department of Basic Nursing Science, College of Nursing, Keimyung University, Daegu, Republic of Korea.
Na-Hyun
NH
Kim
Department of Physiology and Institute of Lifestyle Medicine, Yonsei University Wonju College of Medicine, Wonju, Republic of Korea.
Seung-Kuy
SK
Cha
Department of Physiology and Institute of Lifestyle Medicine, Yonsei University Wonju College of Medicine, Wonju, Republic of Korea. Electronic address: Kong@yonsei.ac.kr.
In Deok
ID
Kong
D000818:Animals; D002118:Calcium / Q000378:metabolism; D002232:Carbocyanines; D005728:Ganglia, Sympathetic / Q000378:metabolism*; D008297:Male; D009474:Neurons / Q000502:physiology*; D018408:Patch-Clamp Techniques; D010388:Pelvis / Q000294:innervation; D051381:Rats; D011963:Receptors, GABA-A / Q000096:biosynthesis*; D001743:Urinary Bladder / Q000294:innervation*; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology
D002232:Carbocyanines; D011963:Receptors, GABA-A; C024286:3,3'-dioctadecylindocarbocyanine; D005680:gamma-Aminobutyric Acid; D002118:Calcium
Autonomic neuron; Bladder; GABA(A) receptor; Major pelvic ganglion neurons