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Biomedical subjects

M Kavaliers

Publications and source records attributed to M Kavaliers.

At least 181 records · Page 10Linked to original sources
PubMed1983

A functional role for an opiate system in snail thermal behavior.

The terrestrial snail Cepaea nemoralis, when placed on a 40 degrees C hot plate, lifts the anterior portion of its foot. The latency of this response is influenced by morphine and by naloxone in a dose-dependent and time-dependent manner. Morphine increases the time taken to respond, whereas naloxone reduces it. Furthermore, naloxone abolishes the effect of morphine. These results indicate that an opiate system may have a role in this behavior, which resembles that reported in vertebrates.

Animals↗
PubMed1983

Tolerance to the morphine-influenced thermal response in the terrestrial snail, Cepea nemoralis.

The terrestrial snail, Cepea nemoralis, displayed stereotyped thermal-avoidance behavior, with morphine increasing and naloxone decreasing the latency of this response. After 5-7 days of daily administration of morphine sulfate (1 microliter of 0.10-10.0 mg/ml) the thermal responses of snails displayed tolerance to morphine. The response latency was reduced to that of saline-treated individuals. Pretreatment with the protein synthesis inhibitor, cycloheximide, blocked the development of tolerance. After termination of chronic treatment with morphine, tolerant snails exhibited withdrawal signs that included increased responsiveness to naloxone, decreased responsiveness to morphine and saline and behavioral alterations suggesting irritation and hyperactivity. These results suggest that the thermally-induced behavior of Cepea can serve as a useful model for the investigation of the development of opioid tolerance and physical dependence in mammals.

Animals↗
PubMed1982

Pinealectomy modifies the thermoregulatory effects of bombesin in goldfish.

Intraventricular administration of the neuropeptide, bombesin, to intact and sham-pinealectomized fish significantly decreased their behaviorally selected internal body temperatures in horizontal thermal gradients. A behavioral hypothermia of 4-7 degrees C was evident regardless of the previous acclimatization temperature (10 or 25 degrees C) and preferred body temperatures selected by individual fish. Pinealectomy increased the body temperatures of all control fish by 2-4 degrees C while markedly reducing the hypothermic effects of administration of bombesin. The hypothermic effects of bombesin were most evident in the pinealectomized fish acclimatized to 10 degrees C. The possible relations between neuropeptides and the pineal gland in the regulation of body temperature are considered.

Animals↗
PubMed1980

Circadian rhythm in the effect of theophylline on the behavioral thermoregulation of the white sucker, Catostomus commersoni.

The temperatures selected by white suckers placed in a thermal gradient were significantly altered by interperitoneal injections of theophylline (25 mg/kg). There was a circadian variation in the effect of theophylline on temperatures selected by individual fish held under constant illumination. Depending on injection time, there was either a significant increase or significant decrease in the temperatures selected. These results are considered in relation to the possible physiological and biochemical effects of theophylline on thermoregulation and circadian rhythms.

Animals↗
PubMedDate not supplied

Levorphanol but not dextrorphan suppresses the foot-lifting response to an aversive thermal stimulus in the terrestrial snail, Cepaea nemoralis.

The terrestrial snail, Cepaea nemoralis, when placed on a surface heated at 40 degrees C lifts the anterior portion of its foot from the source of heat. This stereotyped response, which suggests aversion, can be inhibited by injections of small doses of morphine and levorphanol, but is not affected by similar or larger doses of dextrorphan. It is suggested that the "analgesic" effect of the opiates in these animals involves interaction with stereochemically specific opiate receptors that may be fundamentally similar to those occurring in mammals.

Animals↗
PubMedDate not supplied

Pineal mediation of the thermoregulatory and behavioral activating effects of beta-endorphin.

Intraventricular administration of the opioid peptide, beta-endorphin to goldfish altered their body temperatures and activity levels. Low doses (0.5-5.0 pg g-1 body weight) of beta-endorphin significantly increased behaviorally selected body temperatures while higher doses (15 pg g-1) decreased the preferred temperatures selected in horizontal thermal gradients. There was a significant day-night rhythm in the extent of these effects. These thermoregulatory effects could be blocked and reversed by systemic administration of the opiate antagonist, naloxone, supporting mediation of the thermoregulatory effects at opioid receptors. In addition, administration of naloxone by itself significantly decreased preferred temperature. Removal of the pineal gland significantly increased the preferred temperatures selected by goldfish and eliminated the thermoregulatory effects of beta-endorphin administration in both the day and the night. The behavioral activity effects of beta-endorphin were dependent on the thermal conditions. In fish held at a constant temperature (20 degrees C) beta-endorphin caused a dose-dependent increase in activity, while in individuals held in thermal gradients administration of beta-endorphin had no effects on activity. In both situations naloxone caused a decrease in activity levels. Pinealectomy also eliminated the behavioral activating effects of beta-endorphin, though it had no apparent effects on the actions of naloxone. These results indicate that the pineal gland is involved in the mediation of the thermoregulatory and behavioral activating effects of beta-endorphin. Speculations are made as to the possible mechanisms of action of the pineal gland in mediating the effects of opioid neuropeptides.

Animals↗
PubMedDate not supplied

Prolyl-leucyl-glycinamide reduces aggression and blocks defeat-induced opioid analgesia in mice.

The effects of Prolyl-leucyl-glycinamide (PLG, MIF-1) and the exogenous opiate antagonist naloxone, on aggressive interactions and defeat-induced analgesia were examined in male mice. Both substances reduced the number of bites required to obtain defeat in subordinate mice during aggressive encounters as well as blocking the subsequent defeat-induced analgesia. These results suggest that MIF-1 may function as an endogenous opioid antagonist and have an inhibitory influence on aggression.

Aggression↗