OMEGA-CONOTOXIN-GVIA AND DESIPRAMINE INSENSITIVE NOREPINEPHRINE EFFLUX FROM CARDIAC SYMPATHETIC-NERVE TERMINAL

Using dialysis technique, prominent accumulation of norepinephrine (NE ) in the myocardial interstitial space was observed under local admini stration of a monoamine oxidase inhibitor (pargyline, 10 mM), and a ve sicle uptake inhibitor (reserpine, 10 mu M). Accumulation of NE in the myocardial interstitial space was associated with a reduction of dihy droxyphenylglycol levels. Pretreatment with omega-conotoxin GVIA (10 m u M) or desipramine (10 mu M) did not suppress this response. A brisk increase in dialysate NE levels might occur as a consequence of exocyt otic or neurotransporter insensitive efflux of NE. (C) 1997 Elsevier S cience B.V.