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This Article Full Text Full Text (PDF) All Versions of this Article: 293/4/F1115    most recent 00135.2007v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (3) Citing Articles via Google Scholar Google Scholar Articles by Chen, G.-D. Articles by Lin, T.-B. Search for Related Content PubMed PubMed Citation Articles by Chen, G.-D. Articles by Lin, T.-B.

Descending facilitation of spinal NMDA-dependent reflex potentiation from pontine tegmentum in rats

¹Department of Obstetrics and Gynecology, Chung-Shan Medical University Hospital, ³Department of Physiology, College of Medicine, Chung-Shan Medical University, ²Department of Veterinary Medicine, National Chung-Hsing University, and ⁴Division of Urology, Department of Surgery, Taichung Veterans General Hospital, Taichung; ⁵Department of Nursing, Cardinal Tien College of Healthcare and Management, Taipei; and Departments of ⁶Pharmacy and ⁹Medicine, St. Paul's Hospital, and Departments of ⁷Biotechnology and ⁸Biomedical Engineering, Ming-Chuan University, Taoyuan, Taiwan

Submitted 22 March 2007 ; accepted in final form 16 July 2007

This study was conducted to investigate whether dorsolateral pontine tegmentum stimulation modulates spinal reflex potentiation (SRP) and whether serotonergic neurotransmission is involved in such a modulation. Reflex activities of the external urethra sphincter (EUS) electromyogram in response to a test stimulation (TS; 1/30 Hz) or repetitive stimulation (RS; 1 Hz) on the pelvic afferent nerve in 35 anesthetized rats were recorded with/without synchronized train pontine stimulation (PS; 300 Hz, 30 ms) and/or intrathecal administrations of 10 µl of 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo (F) quinoxaline (NBQX; 100 µM), D-2-amino-5-phosphonovalerate (APV; 100 µM), N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-(2-pyridinyl) cyclohexanecarboxamide trihydrochloride (WAY 100635; 100 µM), and 8-hydroxy-2-(di-n-propylamino)-tetralin (8-OH-DPAT; 100 µM). The TS evoked a single action potential (1.00 ± 0.00 spikes/stimulation), while the RS produced a long-lasting SRP (16.12 ± 1.59 spikes/stimulation) that was abolished by APV (1.57 ± 0.29 spikes/stimulation) and was attenuated by NBQX (7.42 ± 0.57 spikes/stimulation). Synchronized train PS with RS (PS+RS) produced facilitation in RS-induced SRP (25.17 ± 2.21 spikes/stimulation). Intrathecal WAY 100635 abolished the facilitation in SRP as a result of the synchronized PS (14.66 ± 1.58 spikes/stimulation). On the other hand, intrathecal 8-OH-DPAT elicited facilitation in the RS-induced SRP (25.16 ± 1.05 spikes/stimulation) without synchronized PS. Our findings suggest that dorsolateral pontine tegmentum may modulate N-methyl-D-aspartic acid-dependent SRP via descending serotonergic neurotransmission. This descending modulation may have physiological/pharmacological relevance in the neural controls of urethral closure.

long term potentiation; SRP; pontine tegmentum; serotonin; WAY 100635; 8-OH-DPAT

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