Analgesic actions of local anesthetics and cobalt chloride in the rat brain stem.
A low-intensity thermally evoked tail avoidance reflex (LITETAR) was used to study changes in nociceptive response produced by local anesthetics and cobalt chloride microinjected into the dorsal posterior mesencephalic tegmentum (DPMT) of conscious rats. Dose-related prolongation of the LITETAR (e.g., analgesia) was observed when lidocaine, cocaine, and bupivacaine were administered into the DPMT. Analgesic actions were also demonstrated when cobalt chloride was microinjected into the DPMT. The analgesic actions of these different neuronal suppressants provide support for the hypothesis that there exists tonic activity of hyperalgesic processes in the rat brain stem.
Hamann
S R
SR
Department of Anesthesiology, College of Medicine, University of Kentucky, Lexington 40536.
Holtman
J R
JR
Martin
W R
WR
D000700:Analgesics / Q000494:pharmacology*; D000779:Anesthetics, Local / Q000494:pharmacology*; D000818:Animals; D001933:Brain Stem / Q000187:drug effects*; D003035:Cobalt / Q000494:pharmacology*; D005260:Female; D010147:Pain Measurement / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D013681:Tegmentum Mesencephali / Q000502:physiology
D000700:Analgesics; D000779:Anesthetics, Local; D003035:Cobalt; C018021:cobaltous chloride