Barbiturate and picrotoxin-sensitive chloride efflux in rat cerebral cortical synaptoneurosomes.
The effects of various barbiturates and picrotoxin in modifying the efflux of chloride (36Cl-) was studied in a novel subcellular preparation from rat cerebral cortex, the 'synaptoneurosome'. Dilution of synaptoneurosomes pre-loaded with 36Cl- resulted in rapid efflux of 36Cl- that could be measured as early as 10 s following dilution. In the presence of barbiturates such as pentobarbital and hexobarbital there was a significant increase in 36Cl- efflux which was not observed with the pharmacologically-inactive barbiturate, barbital. The effect of barbiturates in enhancing 36Cl- efflux was also stereospecific [(-)-DMBB greater than (+)-DMBB] and reversed by picrotoxin. By contrast, picrotoxin alone significantly inhibited 36Cl- efflux. These data demonstrate pharmacologically relevant Cl- transport for the first time in a subcellular brain preparation.
D000818:Animals; D001463:Barbiturates / Q000494:pharmacology*; D002540:Cerebral Cortex / Q000378:metabolism*; D002712:Chlorides / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D010852:Picrotoxin / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D013329:Structure-Activity Relationship; D013574:Synaptosomes / Q000187:drug effects / Q000378:metabolism*
D001463:Barbiturates; D002712:Chlorides; D010852:Picrotoxin