[Effect of transection or pretreatment of the infraorbital nerve with snake venom on the analgesia induced by electroacupuncture of "Sibai" (ST 2) acupoint in visceral pain rats].

Zhen Ci Yan Jiu 2010 Aug;35(4):281-6

Key Laboratory for Studying Regularities and Mechanism of Acu-moxibustion, Department of Acu-moxibustion, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, China.

Objective: To observe the role of large-diameter fibers of infraorbital nerve (ION) in "Sibai" (ST 2)-electroacupuncture (EA) induced analgesia in visceral pain (VP) rats.

Methods: A total of 36 SD rats were randomized into control, VP, EA, ION transaction, snake venom (SV) and saline groups, with 6 rats in each group. EA(2 Hz/20 Hz) was applied to bilateral "Sibai" (ST 2) for 20 min. VP model was established by intraperitoneal injection of 0.6% acetic acid (10 mL/kg). Bilateral ION were transacted or pretreated by regional application of snake venom to selectively destroy A fibers,respectively. Behavior reactions were assessed by counting abdominal muscular contractions. Meanwhile, c-fos expression in the nucleus of the solitary tract (NTS) and paratrigeminal nucleus (PTN) was displayed by immunohistochemistry.

Results: In comparison with control group, the numbers of abdominal muscular contraction,and c-fos immuno-reaction (IR) positive neurons in both NTS and PTN increased significantly in VP group (P < 0.001); while in comparison with VP group, the numbers of the abdominal contraction, and c-fos IR-positive neurons of both NTS and PTN in EA and SV and saline groups decreased considerably (P < 0.05, P < 0.01). No significant differences were found between ION transaction and VP groups in the abdominal contraction number, and c-fos IR-positive neurons in both NTS and PTN areas,and among EA and SV and saline groups in the numbers of abdominal contraction and c-fos IR-positive neurons of both NTS and PTN (P > 0.05).

Conclusion: The large-diameter (A) fibers of ION are not the major afferent fibers affecting EA-ST 2 induced analgesia in visceral pain rats; and somatic sensory afferents from orofacial areas and visceral pain input converge in the NTS and PTN, which may be the basis of the EA analgesia in the present study.

Download full-text PDF

Source
August 2010
21 Reads

Publication Analysis

Top Keywords

nts ptn
20
neurons nts
16
visceral pain
16
abdominal contraction
12
snake venom
12
numbers abdominal
12
saline groups
12
c-fos ir-positive
12
ir-positive neurons
12
abdominal muscular
8
ion transaction
8
large-diameter fibers
8
analgesia visceral
8
group numbers
8
induced analgesia
8
infraorbital nerve
8
contraction c-fos
8
ptn
6
nts
6
c-fos
5

Similar Publications