Effects of cocaine and desipramine on the neurally evoked overflow of endogenous noradrenaline from the rat heart.
1 Stimulation of postganglionic cardiac sympathetic nerves produced a stimulation frequency-dependent overflow of endogenous noradrenaline from the otherwise isolated rat heart. 2 Such nerve stimulation also produced increases in heart rate. There was significant correlation between heart rate increases and corresponding noradrenaline concentrations in the coronary venous effluent. 3 Cocaine (3 X 10(-5)M) caused a significant reduction in both the noradrenaline overflow and the heart rate increase, produced by nerve stimulation for 1 min at 4 Hz. 4 Desipramine (10(-6)M) caused a significant increase in the noradrenaline overflow produced by stimulation for 1 min (4 Hz) with a mean increase of approximately 60%. There was no significant effect on the heart rate increase produced by such stimulation. 5 The opposite effects of cocaine (3 X 10(-5)M) and desipramine (10(-6)M) on noradrenaline overflow are attributed to differences in the local anaesthetic properties of these agents.
D000818:Animals; D003042:Cocaine / Q000494:pharmacology*; D003891:Desipramine / Q000494:pharmacology*; D004558:Electric Stimulation; D006321:Heart / Q000294:innervation; D009206:Myocardium / Q000378:metabolism*; D009638:Norepinephrine / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D003042:Cocaine; D003891:Desipramine; D009638:Norepinephrine