Dopaminergic and α-adrenergic control of neurotransmission in human right atrium

摘要: The aim of the present study was to investigate dopamine receptor- and alpha-adrenergic receptor-mediated modulation norepinephrine release in human atria. Right atrial appendages were incubated with 3H-norepinephrine, placed superfusion chambers, field-stimulated by platinum electrodes at a frequency 5 Hz. stimulation-induced (S-I) outflow radioactivity taken as an index release. D2-receptor agonist quinpirole (0.03-3 microM) concentration dependently inhibited S-I EC50 0.03 microM. concentration-response curve potently shifted right antagonists domperidone (0.003 microM, pKB approximately 9.2) S(-)-sulpiride (0.1 8.6). D1-receptor antagonist SCH 23390 (1 slightly (pKB 6.9) quinpirole, whereas alpha 2-adrenergic rauwolscine (0.01 1-adrenergic prazosin had no effect. did not affect fenoldopam (0.03 0.3 microM), but (3 enhanced radioactivity. facilitatory effect unaltered prevented microM). UK 14304 (0.01-1 (EC50: 0.06 methoxamine (0.3-30 8.6).(ABSTRACT TRUNCATED AT 250 WORDS)