Dissociation of limbic structures by pharmacological effects of diazepam on electrical self-stimulation in the mouse.
The effect of diazepam was tested on self-stimulation (SS) in 21 mice implanted with a bipolar electrode in the lateral hypothalamus (LH), the dorsolateral hippocampus (HPC) or the lateral entorhinal cortex (LEC). Diazepam, injected i.p. in doses of 0.5, 1 and 2 mg/kg, significantly increased SS rates with electrodes in LH while 4 and 8 mg/kg of diazepam had no significant effect. At low doses, similar increases were seen in mice with LEC electrodes but high doses produced a significant suppression. HPC animals showed an almost total suppression of SS beginning at 2 mg/kg of diazepam; lower doses had no significant effect. The results indicate that entorhinal and hippocampal SS are at least partly independent phenomena; in addition, the suppression of SS by moderate doses of diazepam remains specific to the HPC among the brain structures studied to date.
D000818:Animals; D003975:Diazepam / Q000494:pharmacology*; D004558:Electric Stimulation; D006624:Hippocampus / Q000502:physiology; D007026:Hypothalamic Area, Lateral / Q000502:physiology; D008032:Limbic System / Q000502:physiology*; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D012653:Self Stimulation / Q000187:drug effects*; D013238:Stereotaxic Techniques
D003975:Diazepam