The effects of isolation and handling on reactivity to footshock and tactile dorsal stimulation

Abstract

The effects of isolation and handling on the reactivity of rats to two tactile stimuli were assessed in two experiments. In the first experiment, reactivity to more intense footshock was increased in rats raised in isolation but was not affected by handling by an experimenter. In the second experiment, increased reactivity to airpuff stimuli presented to the dorsal surface of isolation-reared rats was reduced by handling. The data suggest that the effects of handling on shock-motivated behaviors are not due to altered reactivity to shock and that the effect of housing or handling must be considered in behavioral tests in which reactivity to tactile stimulation might playa role as dependent or independent variables.

The effects of age and isolation period on two phases of behavioral response to foot shock in isolation‐reared rats

“…On the other hand, all subjects that were isolated from 26 to 40 days of age showed similar scores for the jumping threshold, which were lower than 0.30 mA irrespective of other differences in the rearing conditions. These facts suggest that isolation during the postweaning stage does not produce stress-induced hyperalgesia, reflected in the increased responsivity to nociceptive stimulus following exposure of a stressor (Illich, King, & Grau, 1995;Jørum, 1988;Vidal & Jacob, 1982, 1986Viken et al, 1982), but rather prevents the increase of the jumping threshold, which should increase with age under natural rearing conditions.…”

“…Several studies, for example, have shown that the reactivity of isolated rats to electric shock increases (Sahakian & Robbins, 1977;Viken, Moore, Knutson, & Fordyce, 1982) while others have found it to decrease (Coudereau, Monier, Bourre, & Frances, 1997;Gentsch et al, 1988;Schwandt, 1993;Viveros et al, 1988). As for the reactivity to restraint, some studies have reported an increases in rats reared in isolation (Gamallo, Villanua, Trancho, & Fraile, 1986;Płaźnik, Pałejko, Stefański, & Kostowski, 1993) whereas others have shown a decrease in reactivity (Giralt & Armario, 1989).…”