W-7 at calmodulin-antagonistic concentrations facilitates noradrenaline release from rat brain cortex slices.
Slices from rat brain occipital cortex were preincubated with [3H]noradrenaline then superfused and stimulated electrically. W-7, 10 mumol/l, enhanced the stimulation-evoked overlow. Binding experiments with W-7 evidenced weak displacement of [3H]yohimbine and no displacement of [3H]prazosin. Release experiments with the addition of clonidine, cocaine or phentolamine provided no evidence for major interference of W-7 with alpha-adrenergic or uptake mechanisms. Facilitation could have been due to inhibition of a calmodulin-dependent enzyme which could not be identified from the present results.
Reimann
W
W
Gödecke Research Institute, Department of Pharmacology, Freiburg, F.R.G.
Köllhofer
U
U
Wagner
B
B
D000818:Animals; D001665:Binding Sites; D002147:Calmodulin / Q000037:antagonists & inhibitors*; D002540:Cerebral Cortex / Q000187:drug effects* / Q000378:metabolism; D003000:Clonidine / Q000494:pharmacology; D008297:Male; D009638:Norepinephrine / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013449:Sulfonamides / Q000494:pharmacology*
D002147:Calmodulin; D013449:Sulfonamides; C017967:W 7; D003000:Clonidine; D009638:Norepinephrine