Stimulus conditions influencing the development of tolerance to repeated cold exposure in rats

Abstract

Tolerance to an environmental cold challenge in rats is eliminated when cold exposure occurs in a context different from the adaptation context, indicating that learning mechanisms playa role in thermoregulation (Riccio, MacArdy, & Kissinger, 1991). This finding, analogous to outcomes obtained with drug tolerance, was investigated in the present study. Experiment 1 demonstrated that a change in both proximal and distal contextual cues disrupts an established cold adaptation, an outcome consistent with the view that associative processes contribute to the tolerance. In Experiment 2, although cold tolerance persisted over a 7-day retention interval, the disruption of tolerance by a shift in context was attenuated with the delay of testing. This finding suggests that the precise stimulus attributes of the context were forgotten over the interval. Experiment 3 demonstrated that cold-tolerance disruption is due to the actual change in context and not to novelty of the test context. Experiment 4 showed that changing the context associated with each cold exposure impaired the development oftolerance. The results of these experiments provide additional evidence that cold tolerance is regulated at least partially by associative learning processes.

Context change and retention interval can have additive, rather than interactive, effects after taste aversion extinction

“…Riccio et aI., 1984). This result contrasts with previous reports suggesting that context-switch effects may diminish overtime (e.g., GisquetVerrier & Alexinsky, 1986;Kissinger & Riccio, 1995;W. R. McAllister & D. E. McAllister, 1963;Perkins & Weyant, 1958;see Riccio et aI., 1994, andRiccio et aI., 1984, for reviews).…”

Learning and the wisdom of the body

“…On both the final adaptation session and the readaptation session, rats were tested in the presence of the usual immersion-paired odor. These results confirm and extend the results of Riccio and colleagues (Kissinger & Riccio, 1995;Riccio, MacArdy, & Kissinger, 1991), and clearly indicate that adaptation to cold-water hypothermia is situationally specific.…”

“…Thus, on the basis of a conditioning analysis of tolerance, we might expect tolerance to be more pronounced when a drug is self-administered cues signaling immersion elicit a CCR-hyperthermiathat compensates for the impending hypothermic stimulation ( just as cues signaling a drug effect elicit a CCR that attenuates the impending pharmacological stimulation). Kissinger and Riccio (1995) described preliminary observations consistent with such an anticipatory hyperthermic CR. In fact, some years earlier, MacArthur (1979) described an anticipatory hypothermic response in a naturalistic study of adaptation to cold water immersion in the muskrat.…”

“…Adaptation to hypothermic stimulation is evidenced by smaller and smaller reductions in body temperature over the course of repeated applications of hypothermic stimulation (induced, for example, by brief immersions in cold water). The results of several experiments by Riccio and colleagues indicate situational specificity of such adaptation to cold (Kissinger & Riccio, 1995;Riccio, MacArdy, & Kissinger, 1991).…”

Sex differences in the behavioural and hypothalamic–pituitary–adrenal response to contextual fear conditioning in rats

“…Moreover, hypoactivity is dependent on the development of contextual fear conditioning and not of shock exposure itself (Daviu et al, 2010;Radulovic et al, 1998), thus ruling out non-specific shock-induced sensitization. Of note, signals associated to the shock may be related not only to the particular context where shock occurred, but also to the experimenter that handled the animals, the way the animals are transported and the particular characteristics and the type of illumination of the room (distal context) (Kissinger and Riccio, 1995). In the present experiment, all these putative distal signals were maintained when the contextual fear conditioning was studied (fear acquisition, context test and extinction sessions), but all them were changed when the animals were exposed to the novel A C C E P T E D M A N U S C R I P T environment.…”