Can Anxiety Tested in the Elevated Plus-maze Be Related to Nociception Sensitivity in Adult Male Rats?

Abstract

Methamphetamine (MA) is one of the most addictive psychostimulant drugs with a high potential for abuse. Our previous studies demonstrated that MA administered to pregnant rats increases pain sensitivity and anxiety in their adult offspring and makes them more sensitive to acute administration of the same drug in adulthood. Because individuals can differ considerably in terms of behaviour and physiology, such as rats that do not belong in some characteristics (e.g. anxiety) to average, can be described as low-responders or high-responders, are then more or less sensitive to pain. Therefore, prenatally MA-exposed adult male rats treated in adulthood with a single dose of MA (1 mg/ml/kg) or saline (1 ml/kg) were tested in the present study. We examined the effect of acute MA treatment on: (1) the anxiety in the Elevated plus-maze (EPM) test and memory in EPM re-test; (2) nociception sensitivity in the Plantar test; (3) the correlation between the anxiety, memory and the nociception. Our results demonstrate that: (1) MA has an anxiogenic effect on animals prenatally exposed to the same drug in the EPM; (2) all the differences induced by acute MA treatment disappeared within the time of 48 hours; (3) there was no effect of MA on nociception per se, but MA induced higher anxiety in individuals less sensitive to pain than in animals more sensitive to pain. In conclusion, the present study demonstrates unique data showing association between anxiety and nociceptive sensitivity of prenatally MA-exposed rats that is induced by acute drug administration.

Methamphetamine self-administration in a runway model of drug-seeking behavior in male rats

“…As indicated in the Introduction of this paper, the presence or absence of aversive/anxiogenic effects after acute administration of meth has produced contradictory and inconsistent results (e.g., Beirami et al, 2017; Etaee et al, 2017; Pometlová et al, 2016). An examination of the subjects’ retreat behavior suggests that, unlike that which we have previously observed in animals running for IV cocaine (e.g., Ettenberg and Geist, 1991; 1993; Guzman and Ettenberg, 2007; Knackstedt et al, 2002), rats running for meth did not exhibit signs of any significant aversive consequences of the drug administration.…”

“…While animal research should be able to more clearly answer this question, attempts to measure the anxiogenic/aversive effects of acute meth have produced contradictory and inconclusive results. Some studies employing an elevated plus maze show meth to be anxiogenic in that treated animals increased their latency to enter or spend time in the open arms of the apparatus (e.g., Beirami et al, 2017; Miladi-Gorji et al, 2015; Pometlová et al, 2016), while other studies have reported the exact opposite result and have suggested that the acute administration of the drug is anxiolytic (e.g., Etaee et al, 2017). In other work, dose-dependent decreases in social interactions have been observed after meth administration and hence may be another indicator of an anxiogenic response in rats (Šlamberová et al, 2010).…”