[Responses of glucose-sensitive neurons and insulin-sensitive neurons in nucleus tractus solitarius to electroacupuncture at auricular concha in rats].
OBJECTIVE
To investigate the central mechanism of hypoglycemic effect induced by ear acupuncture.


METHODS
Extracellular single-unit recordings were carried out in nucleus tractus solitarius (NTS) of rats after infusion of glucose, insulin via jugular venous and electroacupuncture at auricular concha, observing responses of glucose-sensitive neurons and insulin-sensitive neurons in NTS to electroacupuncture stimulation at auricular concha.


RESULTS
There existed glucose-sensitive neurons and insulin-sensitive neurons in NTS. Among glucose-sensitive neurons, inhibitory ones accounted for 37.3%, and excitable ones accounted for 10.9%. Among the insulin-sensitive neurons, excitable ones accounted for 33.3%, and inhibitory ones accounted for 4.9%. When electroacupuncture was given at auricular concha, 49.3% (34/69) of total neurons recorded in NTS showed increase in firing rate, while 4.3% (3/69) showed decrease in firing rate. Among the 34 exciting-responsive neurons, there were 18 neurons responding to glucose infusion with a discharge decreased in frequency, and there were 8 neurons responding to insulin infusion with a discharge increased in firing rate.


CONCLUSIONS
Acupuncture stimulation at auricular concha can irritate the neurons in NTS, which show largely inhibitory and excitable response to glucose and insulin infusion, respectively. The hypoglycemic effect induced by auricular acupuncture possibly results from regulating these neurons' firing activities.
Mei
Zhi-Gang
ZG
Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing 100700, China. meizhigang@gmail.com
Zhu
Bing
B
Li
Yan-Hua
YH
Rong
Pei-Jing
PJ
Ben
Hui
H
Li
Liang
L
D020831:Acupuncture, Ear; D000818:Animals; D015671:Electroacupuncture; D005947:Glucose / Q000494:pharmacology*; D007328:Insulin / Q000494:pharmacology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D017552:Solitary Nucleus / Q000187:drug effects* / Q000502:physiology
D007328:Insulin; D005947:Glucose