Analgesic actions of local anesthetics and cobalt chloride in the rat brain stem

• Published in: Pharmacology, biochemistry and behavior Vol. 43; no. 3; pp. 925 - 927
• Main Authors: Hamann, S.R., Holtman, J.R., Martin, W.R.
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.11.1992; Elsevier Science
• Subjects: Analgesia; Analgesics; Analgesics - pharmacology; Anesthetics, Local - pharmacology; Animals; Biological and medical sciences; Brain stem; Brain Stem - drug effects; Cobalt - pharmacology; Female; Hyperalgesia; Medical sciences; Neuropharmacology; Nociception; Opioid; Pain Measurement - drug effects; Pharmacology. Drug treatments; Rats; Rats, Sprague-Dawley; Tegmentum Mesencephali - physiology; Tonic activity; Nociception; Opioid; Analgesia; Tonic activity; Brain stem; Hyperalgesia; Rat; Rodentia; Central nervous system; Midbrain; Site of action; Local anesthetic; Vertebrata; Mammalia; Analgesic; Cobalt chloride; Animal; Intracerebral administration; Brain (vertebrata)
• ISSN: 0091-3057; 1873-5177
• DOI: 10.1016/0091-3057(92)90426-G

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.