Methylphenidate Reversal of Dexmedetomidine-Induced Versus Ketamine-Induced Sedation in Rats.

Background: Dexmedetomidine and ketamine have long elimination half-lives in humans and have no clinically approved reversal agents. Methylphenidate enhances dopaminergic and noradrenergic neurotransmission by inhibiting reuptake transporters for these arousal-promoting neurotransmitters. Previous studies in rats demonstrated that intravenous methylphenidate induces emergence from isoflurane and propofol general anesthesia.

Dopaminergic psychostimulants cause arousal from isoflurane-induced sedation without reversing memory impairment in rats.

Background: Dopaminergic psychostimulants can restore arousal in anaesthetised animals, and dopaminergic signalling contributes to hippocampal-dependent memory formation. We tested the hypothesis that dopaminergic psychostimulants can antagonise the amnestic effects of isoflurane on visuospatial working memory.

Methods: Sixteen adult Sprague-Dawley rats were trained on a trial-unique nonmatching-to-location (TUNL) task which assessed the ability to identify a novel touchscreen location after a fixed delay.

Oestrous cycle affects emergence from anaesthesia with dexmedetomidine, but not propofol, isoflurane, or sevoflurane, in female rats.

Background: Although sex differences in anaesthetic sensitivity have been reported, what underlies these differences is unknown. In rodents, one source of variability in females is the oestrous cycle. Here we test the hypothesis that the oestrous cycle impacts emergence from general anaesthesia.