Clin Exp Rheumatol. 1999 Nov-Dec; 17(6): 655-62.

The effects of parachlorophenylalanine and naloxone on acupuncture and electroacupuncture modulation of capsaicin-induced neurogenic edema in the rat hind paw. A controlled blind study.

Ceccherelli F, Gagliardi G, Visentin R, Sandona F, Casale R, Giron G.

Observatory on Complementary Medicine, Institute of Anaesthesiology and Intensive Care, University of Padova, A.I.R.A.S., Italy. istaneri@ux1.unipd.it

OBJECTIVE: The aim of this work was to study the effect of pre-treatment with parachlorophenylalanine (PCPA) and posttreatment with naloxone on the modulating action on neurogenic inflammation of manual acupuncture and low intensity (5 mAmp), low frequency (5 Hz) electroacupuncture (EA). METHODS: Edema was induced by the subcutaneous administration of 50 micrograms capsaicin in rat paws. Pre-treatment with intraperitoneal PCPA was given for 3 days: 200 mg/Kg on the first day and 100 mg/Kg on the second and third days. Naloxone (1 mg/Kg) was administered at the end of the stimulation. RESULTS: The results show that naloxone and PCPA reduce the anti-edema effect of both manual acupuncture and EA. Combined administration of the two drugs completely eliminated the effect of manual acupuncture, and decreased but did not abolish the effect of electroacupuncture. CONCLUSION: These results indicate that both the opioid and the serotonergic inhibitory control systems are involved in the modulating action of acupunctural stimulation on neurogenic inflammation.