Related Experiment Video
Updated: Aug 11, 2026

Receptor Autoradiography Protocol for the Localized Visualization of Angiotensin II Receptors
Published on: June 7, 2016
Alpha-receptor-mediated modulation of 3H-noradrenaline release from rat brain cortex synaptosomes
Abstract:
The effects of oxymetazoline and noradrenaline (in the presence of desipramine) on the release of 3H-noradrenaline from rat brain cortex synaptosomes were studied using a superfusion technique. Both drugs (at 1 micrometer concentrations) were found to reduce the depolarization-induced (15 mM K+) release of 3H-noradrenaline. The release-modulating effect of noradrenaline was antagonized by phentolamine and yohimbine. The data provide direct evidence for the hypothesis that alpha-receptors modulating the release of noradrenaline are localized on varicosities of central noradrenergic neurones.
Related Concept Videos
GPCRs Regulate Adenylyl Cylase Activity
Two...
Drugs Acting on Autonomic Ganglia: Stimulants
Ganglionic stimulants activate NM nicotinic receptors in autonomic ganglia, falling into two categories: nicotine mimetics [e.g., lobeline, dimethylpiperazine, tetramethylammonium] and muscarinic receptor agonists [e.g., muscarine, methacholine]. The first category's action is rapid and blocked by nicotinic receptor antagonists, while the second category's action is delayed and blocked by atropine-like agents. Nicotine, an alkaloid, affects the heart rate by stimulating sympathetic or...
Adrenergic Neurons: Neurotransmission
Synthesis: Catecholamine synthesis requires tyrosine, which is taken...
Adrenergic Receptors: β Subtype
Isoprenaline > Adrenaline > Noradrenaline
Neurotransmitter binding to these receptors causes activation of adenylyl cyclase resulting in increased concentrations of cAMP and modulation of calcium ion channels within the cell. They are further classified into β1, β2, and β3 subtypes.
β1-adrenoceptors: β1-adrenoceptors have equal affinities for...
Adrenergic Antagonists: Chemistry and Classification of ɑ-Receptor Blockers
Nonselective α-blockers: Nonselective α-blockers contain haloalkylamine or imidazoline moieties. Phenoxybenzamine, with a haloalkylamine...
Adrenergic Antagonists: Pharmacological Actions of ɑ-Receptor Blockers
α1-blockers: These drugs inhibit α1-adrenoceptors on smooth muscle cells, resulting in vasodilation. This vasodilation lowers blood pressure, making α1-blockers valuable in treating hypertension. Additionally, α1-blockers effectively address urinary obstruction...

