Biomedical subjects
Publications and source records attributed to C Advokat.
Rats who received a tail flick test following repeated injections of 5 mg/kg of morphine were significantly more tolerant than rats who were not tested after each injection. Administration of 0.5 mg/kg of naltrexone hydrochloride, prior to the morphine injections, prevented the development of tolerance, increased analgesic latencies and abolished the difference between tested and nontested animals.
Analgesic tolerance induced by morphine pellets was examined in rats using the nociceptive tail flick reflex. Analgesic responses of animals who received preliminary tail flick tests after morphine implantation were significantly lower than responses of naive, nontested animals. Previously tested animals were also significantly more tolerant to a morphine challenge than nontested animals. A dose response curve to morphine was not obtained, at the doses used here, from previously tested animals, where as naive animals responded to in a dose dependent manner. Environmental modulation of the tail flick represents an elementary form of behavioral plasticity which may prove useful for neural analyses of simple reflex systems.
The development of analgesic tolerance to the nociceptive tail flick test was examined in morphine implanted rats. Animals repeatedly exposed to a nonfunctional tail flick apparatus after implantation, were significantly more tolerant than nonexposed animals, on subsequent tests with the functional apparatus. In contrast, prior exposure to an alternate nociceptive, hot plate test, did not significantly modify tolerance on the tail flick. Facilitation of tolerance, produced by prior tail flick assessment, was maintained for at last one week following the last test, but only if the morphine pellet was not removed. If the pellet was removed the influence of prior analgesic assessment was not retained. The substantial plasticity exhibited by the spinal tail flick reflex suggests the utility of this response for investigations of neural correlates of behavior.
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This study describes the outcome of a token economy treatment applied to 2 distinct patient populations on the same unit of a state psychiatric hospital: individuals with a dual diagnosis of mental retardation and a DSM-IV Axis I diagnosis of either (a) a severe behavior disorder (BD) or (b) a serious and persistent psychiatric disorder (PD). Results showed that patients in the PD group were more likely to complete the treatment (17/20) than those in the BD group (17/31) who were more likely to be terminated from the program (14/31). Individuals who did not complete the program were distinguished early, within the first 3 weeks of treatment. These noncompleters received significantly more fines and earned significantly fewer tokens than those who completed the program. At an average of 2.7 years post-discharge, there was no difference in the proportion of PD (12/16) and BD completers (9/11) and BD noncompleters (3/7) remaining in the community. These data show that diverse populations of patients can be treated within the same token economy program, thereby improving cost effectiveness. Future research should be directed toward characterizing those patients (e.g., BD) less likely to succeed when they enter treatment, and determining if modifications in the program can improve that outcome.