Antinociceptive mechanisms associated with diluted bee venom acupuncture (apipuncture) in the rat formalin test: involvement of descending adrenergic and serotonergic pathways.
In a previous report, subcutaneous injection of diluted bee venom (dBV) into a specific acupuncture point (Zusanli, ST36), a procedure termed apipuncture, was shown to produce an antinociceptive effect in the rat formalin pain model. However, the central antinociceptive mechanisms responsible for this effect have not been established. Traditional acupuncture-induced antinociception is considered to be mediated by activation of the descending pain inhibitory system (DPIS) including initiation of its opioidergic, adrenergic and serotonergic components. The purpose of the present study was to investigate whether the antinociceptive effect of apipuncture is also mediated by the DPIS. Behavioral experiments verified that apipuncture significantly reduces licking behavior in the late phase of formalin test in rats. This antinociceptive effect of apipuncture was not modified by intrathecal pretreatment with naltrexone (a non-selective opioid receptor antagonist), prazosin (an alpha1 adrenoceptor antagonist) or propranolol (an beta adrenoceptor antagonist). In contrast, intrathecally injected idazoxan (an alpha2 adrenoceptor antagonist) or intrathecal methysergide (a serotonin receptor antagonist) significantly reversed apipuncture-induced antinociception. These results suggest that apipuncture-induced antinociception is produced by activation of alpha2 adrenergic and serotonergic components of the DPIS.
Kim
Hyun Woo
HW
Department of Veterinary Physiology, College of Veterinary Medicine and School of Agricultural Biotechnology, Seoul National University, San 56-1, Shilim-dong, Kwanak-gu, Seoul 151-742, South Korea.
Kwon
Young Bae
YB
Han
Ho Jae
HJ
Yang
Il Suk
IS
Beitz
Alvin J
AJ
Lee
Jang Hern
JH
D026881:Acupuncture / Q000379:methods*; D000320:Adrenergic Fibers / Q000187:drug effects* / Q000502:physiology; D000700:Analgesics / Q000494:pharmacology*; D000818:Animals; D001514:Bee Venoms / Q000494:pharmacology*; D001516:Bees; D008297:Male; D009434:Neural Pathways / Q000187:drug effects / Q000502:physiology; D010147:Pain Measurement / Q000187:drug effects* / Q000379:methods; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000502:physiology*
D000700:Analgesics; D001514:Bee Venoms; D012701:Serotonin