Parenterally administered kainic acid
induces a persistent hyperalgesia in the mouse and rat
by
Giovengo SL, Kitto KF, Kurtz HJ, Velazquez RA, Larson AA
Department of Veterinary Pathobiology,
University of Minnesota,
295 AnSci/VetMed Building,
1988 Fitch Avenue, St. Paul, USA
Pain 1999 Nov 1; 83(2):347-358

ABSTRACT

Nociceptive primary afferent C-fibers express a subset of glutamate receptors that are sensitive to kainic acid. Thus, we tested the possibility that activation of these receptors alters nociception. Intraperitoneal (i.p.) injection of kainic acid induced a persistent thermal hyperalgesia, when tested using the hot plate (mice) and tail flick (mice and rats) assays, and mechanical hyperalgesia when tested using von Frey monofilaments (rats), but had no effect on acetic acid-induced chemical nociception (mice). When administered i.p., 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), an (R,S)-alpha-amino-3-hydroxy-5-methylisoxazole-4-proprionic acid HBr/kainate (AMPA/KA) antagonist, completely blocked hyperalgesia. When injected intrathecally (i.t.), kainic acid itself failed to induce hyperalgesia and AMPA/KA antagonists given i.t. also failed to attenuate the hyperalgesic effect of kainic acid administered i.p., indicating that the spinal cord is not the primary site of action. Kainic acid injected subcutaneously in the back of mice decreased response latencies in the hot plate and tail flick assays, indicating that hyperalgesia is achieved by a variety of parenteral routes of injection. Histological evaluation of rat spinal cord and dorsal root ganglia revealed no neurodegenerative changes 24 h after kainic acid. Together these data suggest that a persistent hyperalgesia results from the transient activation of AMPA/KA receptors that are located outside the spinal cord, perhaps on the distal projections of primary afferent fibers.

Opioids
Cocaine
Cannabis
Gabapentin
Fibromyalgia
Buprenorphine
Antidepressants
Pain and depression
Prozac as a painkiller
Treating pain seriously
The pain of fibromyalgia
Antidepressants for pain-relief
Cannabinoids, opioids and pain

Refs
and further reading

HOME
HedWeb
Nootropics
cocaine.wiki
Future Opioids
BLTC Research
MDMA/Ecstasy
Superhapiness?
Utopian Surgery?
The Abolitionist Project
The Hedonistic Imperative
The Reproductive Revolution
Critique of Huxley's Brave New World

The Good Drug Guide
The Responsible Parent's Guide
To Healthy Mood Boosters For All The Family