Influence of electro-acupuncture on the release of substance P and the potential evoked by tooth pulp stimulation in the trigeminal nucleus caudalis of the rabbit.
The effects of electro-acupuncture (EAP) on the release of substance P (SP) and the responses evoked by tooth pulp stimulation (ST) in superficial layers of the trigeminal nucleus caudalis (Vc-I,II) were studied in rabbits. ST evoked increase in release of immunoreactive SP (iSP). This increase was inhibited by EAP in 9 of 13 animals. The potentials evoked by ST were composed of two main components with latency times of ca 4.3 msec and ca. 9.4 msec. The latter component, reflecting the excitation of A delta fibers, was significantly inhibited by CP-96,345 (3 mg/kg, i.v.), an SP antagonist. EAP also inhibited the latter component in 8 of 11 animals. These results suggest that one of the mechanisms of analgesia induced by EAP is inhibition of stimulus-evoked SP release in the Vc-I,II.
Yonehara
N
N
Department of Pharmacology, Faculty of Dentistry, Osaka University, Japan.
Sawada
T
T
Matsuura
H
H
Inoki
R
R
D000818:Animals; D003782:Dental Pulp / Q000502:physiology*; D004558:Electric Stimulation; D015671:Electroacupuncture; D005071:Evoked Potentials; D008297:Male; D011817:Rabbits; D011930:Reaction Time; D013373:Substance P / Q000378:metabolism*; D014275:Trigeminal Caudal Nucleus / Q000378:metabolism / Q000502:physiology*
D013373:Substance P