内脏痛觉过敏状态下脊髓内突触传递的可塑性研究

应用膜片钳技术，在带内脏传入神经的脊髓片和急性分离的腰骶髓后连合核（DCN）神经元瓯旧希芯磕谠嗤淳豕糇刺履谠嗤淳跣畔⒋莸募顾枘诨莆被崂嗪碗睦嗌窬葜试谕淮タ伤苄员浠械淖饔眉鞍诨疲佣髂谠嗌撕π孕畔⒃诩顾枘诘拇莺偷髦苹硪约翱⑿乱┖椭瘟颇谠嗤吹姆椒ㄌ峁├砺垡谰荨

Electrophysiological and morphological properties of neurons in the sacral dorsal commissural nucleus (SDCN) were examined using whole-cell recordings with biocytin-filled electrodes in transverse and/or longitudinal slices of mature rat spinal cord. Neurons were categorized into three groups according to their discharge in response to suprathreshold depolarizing pulses; neurons with tonic and phasic firing patterns, and neurons that fired in bursts arising from a Ca2+-dependent hump. All tonic neurons had axons/collaterals projecting to the intermediolateral area but none to the funiculi, suggesting that they function as interneurons in local autonomic reflexes. Many axons/collaterals of all phasic neurons lay within the DCN, suggesting that they integrate segmental and descending inputs. Neurons with Ca2+-dependent humps had axons/collaterals extending into one of the funiculi, suggesting that they project intersegmentally or to the brain. Ca2+ hump neurons also had more axons/collaterals within the DCN and fewer in the intermediolateral area than tonic neurons. The results also indicated the convergence of the visceral and somatic primary afferent inputs from the pelvic region onto the DCN neurons. The above results are an important step toward defining the cellular pathways and modulation mechanisms regulating the visceral transmission in the spinal cord, and are applicable to develop new analgesic drugs for curing visceral pain.