Tetanization-induced pelvic-to-pudendal reflex plasticity in anesthetized rats.
Reflex plasticity between pelvic afferent and pudendal efferent nerve fibers was examined in anesthetized rats. Brief high-frequency electric stimulation (300 pulses at 100 Hz) of the pelvic nerve afferent fiber produced a long-lasting potentiation of the pelvic-to-pudendal reflex (PPR). This tetanization-induced potentiation was abolished by a selective N-methyl-D-aspartate (NMDA) receptor antagonist and attenuated by a non-NMDA excitatory amino acid receptor antagonist. However, the GABA(A)-receptor antagonist had no effect on this potentiation. Both intrathecal glutamate (0.1 mM, 2-5 microl it) and NMDA (0.1 mM, 2-5 microl it) induced a potentiation of PPR similar to that of tetanization. Agonist-induced potentiation was shorter than tetanization-induced potentiation. The duration of the contraction wave of intraurethral pressure, elicited by PPR, was elongated by tetanization-induced potentiation, whereas the peak pressure was not affected. All these results demonstrate that brief high-frequency stimulation of the pelvic nerve afferent fiber can induce a distinct and long-lasting modulation in PPR activity and this change may be involved in nociceptive C afferent-induced obstructive urinary dysfunctions.
Department of Physiology, College of Medicine, Chung-Shan Medical University, No. 110, Chang-Kuo North Rd. 1st Section, Taichung, Taiwan 10018. tblin@csmu.edu.tw
Tzer-Bin
TB
Lin
D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D003655:Decerebrate State; D004558:Electric Stimulation; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D005260:Female; D018756:GABA Antagonists / Q000494:pharmacology; D058787:GABA-A Receptor Antagonists; D018698:Glutamic Acid / Q000494:pharmacology; D017774:Long-Term Potentiation / Q000502:physiology; D016202:N-Methylaspartate / Q000494:pharmacology; D009424:Nervous System Physiological Phenomena; D009473:Neuronal Plasticity; D010388:Pelvis / Q000294:innervation* / Q000502:physiology*; D011810:Quinoxalines / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D012018:Reflex / Q000187:drug effects; D014633:Valine / Q000031:analogs & derivatives* / Q000494:pharmacology
D018690:Excitatory Amino Acid Agonists; D018691:Excitatory Amino Acid Antagonists; D018756:GABA Antagonists; D058787:GABA-A Receptor Antagonists; D011810:Quinoxalines; C062865:2,3-dioxo-6-nitro-7-sulfamoylbenzo(f)quinoxaline; D018698:Glutamic Acid; D016202:N-Methylaspartate; C056639:2-amino-5-phosphopentanoic acid; D014633:Valine; D001640:Bicuculline