Zhou S Y, Goshgarian H G
Department of Anatomy and Cell Biology, Wayne State University, School of Medicine, Detroit, Michigan 48201, USA.
Exp Neurol. 1999 Dec;160(2):446-53. doi: 10.1006/exnr.1999.7213.
The present study investigates the effect of 5-hydroxytryptophan (5-HTP), a serotonin precursor, on crossed phrenic nerve activity (CPNA) in rats subjected to a left C2 spinal cord hemisection. Electrophysiological experiments were conducted on anesthetized, vagotomized, paralyzed, and artificially ventilated rats to assess phrenic nerve activity. The left phrenic nerve lost rhythmic activity due to the disruption of the bulbospinal respiratory pathways following spinal cord hemisection. Activity was induced in the left phrenic nerve (CPNA) by temporary asphyxia. 5-HTP administration increased CPNA during asphyxia in the left phrenic nerve in a dose-dependent fashion. Specifically, in a group of eight animals, application of 5-HTP at 0.5, 1.0, and 2.0 mg/kg significantly increased CPNA by 102.2+/-18.5%, 200.8+/-58.1%, and 615.0+/-356.9% compared with predrug control values, respectively. 5-HTP-induced increases in CPNA were reversed by methysergide (2-6 mg/kg, i.v.), a serotonin receptor antagonist. The results suggest that serotonin is involved in the modulation of crossed phrenic nerve activity following spinal cord injury.
本研究调查了5-羟色氨酸（5-HTP），一种血清素前体，对左侧C2脊髓半横断大鼠膈神经交叉活动（CPNA）的影响。在麻醉、迷走神经切断、麻痹并人工通气的大鼠上进行电生理实验，以评估膈神经活动。由于脊髓半横断后延髓脊髓呼吸通路中断，左侧膈神经失去节律性活动。通过暂时窒息在左侧膈神经中诱导出活动（CPNA）。给予5-HTP可使窒息期间左侧膈神经的CPNA呈剂量依赖性增加。具体而言，在一组八只动物中，与给药前对照值相比，分别给予0.5、1.0和2.0mg/kg的5-HTP可使CPNA显著增加102.2±18.5%、200.8±58.1%和615.0±356.9%。5-HTP诱导的CPNA增加可被血清素受体拮抗剂麦角新碱（2-6mg/kg，静脉注射）逆转。结果表明，血清素参与脊髓损伤后膈神经交叉活动的调节。
