Repetitive exposure to the hot-plate test produces stress induced analgesia and alters beta-endorphin neuronal transmission within the periaqueductal gray of the rat.
Repetitive exposure of rats to a hot plate induced a novel non-opioid form of stress induced analgesia. The exposure caused a persistent 1.5-2 s increase in tail flick latency which was not attenuated by systemic naltrexone, but was completely inhibited by systemic MK-801. Concomitantly, alterations occurred in the ability to pharmacologically distinguish multiple beta-endorphin receptors in the periaqueductal gray. Thus, in response to different forms of stress, different pathways may be activated by beta-endorphin, resulting in stress induced analgesias with varied pharmacological characteristics (e.g., opioid and non-opioid).
Hawranko
A A
AA
Department of Pharmacology/Toxicology, Robert C. Byrd Health Sciences Center of West Virginia University, School of Medicine, Morgantown 26506.
Monroe
P J
PJ
Smith
D J
DJ
D000595:Amino Acid Sequence; D000698:Analgesia; D000818:Animals; D003570:Cytidine Triphosphate / Q000494:pharmacology; D016291:Dizocilpine Maleate; D006361:Heating; D008297:Male; D008845:Microinjections; D008969:Molecular Sequence Data; D009020:Morphine; D009292:Narcotic Antagonists; D010146:Pain / Q000503:physiopathology; D010487:Periaqueductal Gray / Q000378:metabolism / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013312:Stress, Physiological / Q000378:metabolism / Q000503:physiopathology*; D009435:Synaptic Transmission; D001615:beta-Endorphin / Q000378:metabolism*
D009292:Narcotic Antagonists; D001615:beta-Endorphin; D003570:Cytidine Triphosphate; D016291:Dizocilpine Maleate; D009020:Morphine