Exogenous galanin regulates capsaicin-evoked substance P release from primary cultured dorsal root ganglion neurons.
OBJECTIVE
To determine the effect of exogenous galanin on capsaicin-evoked substance P (SP) release from primary cultured embryonic rat dorsal root ganglion (DRG) neurons.


METHODS
DRG was dissected out from embryonic 15-day-old Wistar rat and cultured as dissociated cells for 2 days then exposed to galanin (1 nmol/L, 10 nmol/L, 100 nmol/L). After 4 days incubation with exogenous galanin, the levels of mRNAs for SP and vanilloid receptor 1 (VR1) and protein for VR1 were estimated by RT-PCR and Western blot, respectively. Basal SP release and capsaicin-evoked SP release levels were measured by radioimmunoassay (RIA).


RESULTS
The amount of VR1 mRNA and VR1 protein expression and capsaicin-evoked SP release in cultured DRG neurons increased significantly after incubation with exogenous galanin compared with control DRG neurons at the same time point, whereas the amount of SP mRNA and basal SP release were not affected after incubation with exogenous galanin.


CONCLUSIONS
Exogenous galanin may promote capsaicin-evoked SP release from primary cultured DRG neurons. The elevation of the levels of VR1 mRNA and VR1 protein induced by exogenous galanin implicated that VR1 may be involved in the mechanisms of SP release evoked by capsaicin.
Yang
Xiangdong
X
Department of Nephrology, Shandong University Qilu Hospital, Jinan 250012, China.
Liu
Zhen
Z
Wang
Lihong
L
Liu
Huaxiang
H
Wang
Huaijing
H
Li
Zhen-Zhong
ZZ
D000704:Analysis of Variance; D000818:Animals; D002211:Capsaicin / Q000494:pharmacology; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D019004:Galanin / Q000008:administration & dosage / Q000502:physiology*; D005727:Ganglia, Spinal / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D007509:Irritants / Q000494:pharmacology; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D011984:Sensory Receptor Cells / Q000187:drug effects* / Q000378:metabolism; D018709:Statistics, Nonparametric; D013373:Substance P / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D050916:TRPV Cation Channels / Q000235:genetics / Q000378:metabolism
D007509:Irritants; D012333:RNA, Messenger; D050916:TRPV Cation Channels; C494484:TRPV1 receptor; D013373:Substance P; D019004:Galanin; D002211:Capsaicin