Related Experiment Video
Updated: Sep 3, 2026

Impact of Intracardiac Neurons on Cardiac Electrophysiology and Arrhythmogenesis in an Ex Vivo Langendorff System
Published on: May 22, 2018
Effects of tetrandrine on cardiac noradrenaline release evoked by electrical stimulation
Abstract:
The effects of tetrandrine (TD) on endogenous cardiac noradrenaline (NA) release evoked by electrical stimulation were investigated in perfused guinea pig hearts. The overflow of cardiac NA and its intraneuronal metabolite 3,4-dihydroxyphenylethyleneglycol (DOPEG) were determined by high pressure liquid chromatography (HPLC). In the presence of TD, the release of NA evoked by either nerve ganglion-stimulation or cardiac field-stimulation was significantly reduced (P < 0.01). The overflow of DOPEG was markedly enhanced (P < 0.01). TD inhibited cardiac endogenous NA release resulting from activation of the sympathetic nerve terminals within the myocardium, and increased the release of DOPEG, indicating that TD could result in a loss of NA from storage vesicles or activate monoamine oxidase in axoplasma, which could be detected by markedly increased DOPEG release. These effects of TD may be associated with its property of calcium antagonist.
Related Concept Videos
Adrenergic Neurons: Neurotransmission
Synthesis: Catecholamine synthesis requires tyrosine, which is taken...
Adrenergic Agonists: Indirect-Acting Agents
One mechanism involves depleting stored catecholamines by displacing them from synaptic vesicles. These agents, known as "displacers," are transported into vesicles at the expense of noradrenaline. Examples include amphetamine and tyramine, which lack a catechol moiety, resulting in prolonged action, improved oral bioavailability, and...
Drugs Affecting Neurotransmitter Release or Uptake
Drugs Affecting Neurotransmitter Synthesis
Antiarrhythmic Drugs: Class II Agents as β-Adrenergic Blockers
Heart Failure Drugs: Inhibitors of Renin-Angiotensin System

