Picrotoxin is a plant alkaloid that is often used to block the activity of neuronal GABA and glycine receptors. However, the mechanism by which picrotoxin inhibits these receptors is still in debate. In this study, we investigated the picrotoxin inhibition on perch-rho subunits expressed heterologously in Xenopus laevis oocytes, and on native GABA(C) receptors of perch bipolar cells. Both compe...

The present study investigates whether clonazepam exerts its antimyoclonic action through a GABA independent mechanism. We have studied the antimyoclonic effect of clonazepam and compared it with that of aminooxyacetic acid (AOAA), a GABA transaminase inhibitor, against myoclonus induced by picrotoxin, a GABA receptor antagonist and allylglycine, a drug which inhibits synthesis and release of G...

The external loop linking the M2 and M3 transmembrane domains is crucial for coupling agonist binding to channel gating in the glycine receptor chloride channel (GlyR). A substituted cysteine accessibility scan previously showed that glycine activation increased the surface accessibility of 6 contiguous residues (Arg271-Lys276) toward the N-terminal end of the homomeric alpha1 GlyR M2-M3 loop. ...

The presence of homooligomeric and heterooligomeric glycine receptors (GlyRs) on the Mauthner (M) cell in the isolated medulla of 52-h-old zebrafish larvae was investigated by analysis of the effects of picrotoxin on glycine-gated channels and on glycinergic miniature inhibitory postsynaptic currents (mIPSCs). Two functionally different GlyRs have been previously described on the M cell. The ef...

Pretreatment with 5-hydroxytryptophan (5-HTP), a precursor of 5-HT, antagonised while pretreatment with p-chlorophenylalanine (PCPA), a 5-HT depletor, potentiated the myoclonus induced by picrotoxin, a GABA antagonist. Pretreatment with aminooxyacetic acid (AOAA), a GABA transaminase inhibitor, antagonised picrotoxin-induced myoclonus. The combined effect of the least protective doses of AOAA a...

The effects of naloxone and picrotoxin were determined alone and in conjunction with pentobarbital, diazepam or clonazepam, in pigeons responding under a multiple fixed-ratio 30-response, fixed-interval 5-min schedule of food presentation. Naloxone (10.0-80.0 mg/kg i.m.) and picrotoxin (0.1-0.56 mg/kg i.m.) alone produced only dose-related decreases in responding in both fixed-ratio and fixed-i...

The effects of Tilia plathphyllos scop. in a nervous disorder, including seizure was reported in traditional literatures. In the present investigation, the effects of methanolic extract of T. plathyphyllos on seizure induced by picrotoxin and pentylentetrazole were studied in mice. In this experimental study, groups of 5 animals pretreated with doses of 100, 200 and 300 mg/kg of methanolic extr...