One of the exceptional properties of the brain is its ability to acquire new knowledge through learning and to store that information through memory. The epigenetic mechanisms linking changes in neuronal transcriptional programs to behavioral plasticity remain largely unknown. Here, we identify the epigenetic signature of the neuronal enhancers required for transcriptional regulation of synaptic plasticity genes during memory formation, linking this to Reelin signaling.
The effect of the GABAA antagonists, bicuculline and picrotoxin, in the hot plate and writhing tests in mice and the paw-pressure test in rats was assessed. Subconvulsant doses of bicuculline (1.3-4 mumol kg-1, s.c.) or picrotoxin (0.8-2.5 mumol kg-1, s.c.) induced a dose-related increase in latency of licking in the hot plate test in mice, whereas subconvulsant doses of strychnine and thiosemicarbazide (0.9 and 6 mg kg-1, s.c. respectively), did not modify the threshold to thermal stimuli in mice.
The Journal of Pharmacology and Experimental Therapeutics
GABA(A) receptors have been implicated in mediating several acute effects of ethanol including anxiolysis, ataxia, sedation/hypnosis, and anticonvulsant activity. Ethanol sensitivity of neurons has been associated with expression of alpha1 subunit-containing receptors. The objective of this study was to determine the contribution of alpha1 subunit containing receptors to ethanol responses in comparison to neurosteroids and other anesthetics using GABA(A) receptor alpha1 subunit knockout mice.
Joint manipulation has long been used for pain relief. However, the underlying mechanisms for manipulation-related pain relief remain largely unexplored. The purpose of the current study was to determine which spinal neurotransmitter receptors mediate manipulation-induced antihyperalgesia. Rats were injected with capsaicin (50 microl, 0.2%) into one ankle joint and mechanical withdrawal threshold measured before and after injection. The mechanical withdrawal threshold decreases 2 h after capsaicin injection.
The physiological and pharmacological properties of taurine-induced responses were investigated in dopaminergic (DA) neurones from the ventral tegmental area (VTA) of young rats aged 1-13 postnatal days, either in acute brain slices or acutely dissociated neurones. When whole-cell responses were recorded from current-clamped neurones using the gramicidin-perforated technique, the application of taurine (0.01-30 mm) accelerated firings and induced membrane depolarization.
Bilobalide, a constituent of Ginkgo biloba, has neuroprotective properties. Its mechanism of action is unknown but it was recently found to block GABA(A) receptors. The goal of this study was to test the potential role of a GABAergic mechanism for the neuroprotective activity of bilobalide. In rat hippocampal slices exposed to NMDA, release of choline indicates breakdown of membrane phospholipids. NMDA-induced choline release was almost completely blocked in the presence of bilobalide (10 microM) and under low-chloride conditions.
Zhongguo Yao Li Xue Bao = Acta Pharmacologica Sinica
AIM: To study the effect of 6,7-dinitroquinoxaline-2,3-dione (DNQX) and bicuculline (Bic) on benzyl-penicillin-induced-epilepsy (PIE) and electroacupuncture (EA) antiepilepsy in rats. METHODS: Epilepsy was elicited by intra-hippocampal microinjection of benzylpenicillin in rats. The analysis of electroencephalogram (EEG) and power spectrum was used to measure the extent of convulsion. RESULTS: EA or DNQX (1 microgram) showed partial inhibitory effect on PIE. EA + DNQX caused further inhibition of PIE, and Bic attenuated EA antiepileptic effect.