Descending inhibitory modulation of nucleus raphes magnus in cardiac nociception in rats and its pathway
10.13481/j.1671-587x.20140310
- VernacularTitle:中缝大核对大鼠心脏伤害性感受的下行抑制性调控作用及其调控通路
- Author:
Na SUN
;
Ligang NIU
;
Lingheng KONG
;
Juanxia ZHU
;
Yan XU
;
Jianqing DU
- Publication Type:Journal Article
- Keywords:
nucleus raphes magnus;
cardiac nociception;
dorsolateral funiculus;
electrical stimulation;
electromyogram;
5-hydroxytryptamine
- From:
Journal of Jilin University(Medicine Edition)
2014;(3):513-518
- CountryChina
- Language:Chinese
-
Abstract:
Objective To observe the cardiosomatic motor reflex (CMR)of rats, and to clarify the descending modulation of nucleus raphes magnus (NRM)in cardiac nociception and its pathway.Methods 34 male healthy SD rats were randomly divided into NRM electrical stimulation group (n=8 ), NRM stimulation combined with dorsolateral funiculus (DLF ) transection group (n= 8 ), NRM stimulation combined with antagonist of 5-hydroxytryptamine (5-HT)methysergide intrathecal administration group (n=18).The rat model of CMR was established through inj ecting capsaicin into the pericardial sac of the rats in various groups. The electromyogram (EMG) response of dorsal spinotrapezius muscle was used as detection index, and by placing the stimulation electrode in NRM and (or)intrathecal catheterization, the descending inhibitory modulation of NRM in CMR and the influence of DLF tansection or methysergide intrathecal administration in descending inhibitory modulation of NRM were observed.Results Compared with before stimulation,the EMG response was decreased after NRM electrical stimulation (75 μA) (P<0.05 );after bilateral DLF transection, the EMG response after NRM stimulation was significantly increased compared with before DLF transection (P<0.05 ), and there was no significant difference compared with its control (P> 0.05 ). In addition, after intrathecal administration of methysergide,the EMG response after NRM stimulation was significantly increased compared with before intrathecal treatment of methysergide (P<0.05),but it was still significantly smaller than that of its control (P<0.05). Conclusion Cardiac nociception evoked by capsaicin stimulation is subject to descending inhibitory modulation from NRM,and the descending inhibition from NRM is conveyed via the DLF and partially mediated by endogenous 5-HT system.
