P D Pezalla

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When isolated rat pars intermedia cells were incubated for 10 min with radioactive amino acids, one major labeled protein with a molecular weight of 30,000 +/- 1500 was extracted. This protein was shown to contain in its sequence the antigenic determinants for corticotropin and beta-melanotropin by immunoprecipitation. When the radioactivity incorporated(More)
1. Crude extracts of Limulus CNS cause hyperglycemia in Orconectes immunis and expand chromatophores in Uca pugilator. 2. The hyperglycemic action is due to a previously unknown polypeptide (LHGF) with an estimated molecular weight of 6400 daltons. LHGF is inactivated by hydrogen peroxide, pepsin, and protease, but unaffected by trypsin and brief boiling.3.(More)
Morphine sulfate is a weak analgesic in the frog Rana pipiens pipiens, causing a slight increase in nociceptive threshold at a dose of 10 mg/kg and a pronounced increase at 100 mg/kg. Morphine-induced analgesia persists for at least 165 min and is significantly attenuated by naloxone. The analgesic doses of morphine are well below the lethal dose and are(More)
Intraspinal injection of levorphanol (3 micrograms) at the lumbar area of the leopard frog, Rana pipiens, induced analgesia which was completely blocked by co-injection of naloxone (3 micrograms), whereas dextrorphan (3 micrograms) induced analgesia which was unaffected by naloxone. Subcutaneous levorphanol (20 or 80 mg/kg) induced a dose-dependent(More)
Spinal administration of low doses of dynorphin, beta-endorphin or Met-enkephalin produces a potent, dose-dependent increase in the nociceptive threshold in the unanesthetized frog, Rana pipiens. Nociceptive thresholds were determined by using the acetic acid test, previously shown to be a sensitive indicator of antinociception in this amphibian species. Of(More)
Immobilization of frogs for 1 h induces analgesia which is blocked but not reversed by low doses of naloxone. After 9 days of daily immobilization for 1 h, the treatment fails to cause analgesia thus indicating that tolerance has developed. Animals tolerant to immobilization-induced analgesia do not show cross-tolerance to the analgesic action of morphine.(More)