Restraint stress attenuates nicotine's locomotor stimulant but not discriminative stimulus effects in rats

Abstract

Stress enhances the locomotor stimulant and discriminative stimulus effects of several addictive drugs (e.g., morphine) in rodents, yet interactions between stress and nicotine’s effects in these behavioral models have not been well established. To this end, the current studies examined the effects of restraint stress on nicotine-induced locomotor activity and nicotine discrimination in rats. We used a novel approach in which onset of stress and nicotine administration occurred concurrently (i.e., simultaneous exposure) to simulate effects of stress on ongoing tobacco use, as well as a more traditional approach in which a delay was imposed between stress and nicotine administration (i.e., sequential exposure). Simultaneous exposure to stress reduced the rate of locomotor sensitization induced by daily injections of nicotine (0.4 mg/kg, s.c.). A lower dose of nicotine (0.1 mg/kg, s.c.) produced modest effects on activity that were generally unaffected by simultaneous exposure to stress. Sequential exposure to stress and nicotine (0.4 mg/kg, s.c.) slightly suppressed nicotine-induced activity, but did not influence rate of locomotor sensitization. Neither simultaneous nor sequential exposure to stress influenced the discriminative stimulus effects of nicotine (0.01 – 0.2 mg/kg, s.c.). These data show that restraint stress reduces nicotine’s locomotor stimulant effects, particularly when onset of stress and nicotine exposure occurs simultaneously, but does not influence nicotine discrimination. These findings contrast with the ability of stress to enhance the effects of other drugs in these models. This study also suggests that studying the influence of simultaneous stress exposure on drug effects may be useful for understanding the role of stress in addiction.

Short-term stress significantly decreases morphine analgesia in trigeminal but not in spinal innervated areas in rats

“…In the actimeter test, our results show that FSS animals moved slightly less than control ones, which is in line with previous studies [37,38]. In addition, at the tested doses, morphine did not significantly alter the spontaneous locomotion of control animals and reversed the effect detected on animals under FSS.…”

Nicotine-Cadmium Interaction Alters Exploratory Motor Function and Increased Anxiety in Adult Male Mice

“…A group of n = 6 mice received 1.4 mg/Kg BW of cadmium chloride prepared in normal saline (intramuscular). Another group received 0.4 mg/Kg BW of nicotine (subcutaneous) [ 35 , 36 ] while a combined treatment group received nicotine (subcutaneous; 0.4 mg/Kg) and cadmium (intramuscular 1.4 mg/Kg) [ 37 , 38 ]. The control was treated with normal saline (subcutaneous) for the duration of the experiment (Table S1 in the Supplementary Material available online at http://dx.doi.org/10.1155/2014/359436 ).…”

Consequence of Two Protocols of Social Defeat Stress on Nicotine-Induced Psychomotor Effects in Mice

“…For example, Kita et al, 1999 [49] found that rats receiving nicotine immediately after each session of chronic psychological stress (witnessing other rats receiving footshock stress) presented enhanced nicotine-induced sensitization at 5 and 10 days of the combined treatment. On the other hand, Harris et al, 2014 [50], found that simultaneous exposure to nicotine during chronic restraint stress prevented the short-term locomotor suppression induced by the stress protocol, although no long-term effects on nicotine locomotor response were observed (see also [46]). Thus, not only the type of stressor, but also the timing of nicotine and stress exposures may be critical to determine the outcomes of stress exposure on nicotine-induced locomotor effects.…”