Related Experiment Video
Updated: Jun 4, 2026

Contractility Measurements on Isolated Papillary Muscles for the Investigation of Cardiac Inotropy in Mice
Published on: September 17, 2015
Effect of α2-Adrenergic Receptor Stimulation on Isolated Rat Heart during Puberty after Hypokinesia
M I Sungatullina1, R I Zaripova1, A M Sadykov1
1Kazan (Volga Region) Federal University, Kazan, Russia.
Abstract:
We studied the effect of α2-adrenoreceptor stimulation on functional parameters of Langendorff-isolated heart from pubertal rats subjected to restriction of motor activity during the early postnatal ontogeny. Clonidine hydrochloride, an agonist of α2-adrenoreceptors, was used at concentrations of 10-9-10-6 M. After restriction of motor activity, stimulation of α2-adrenoreceptors with clonidine at the studied concentrations had a positive inotropic effect. α2-Adrenoreceptor stimulation led to a dose-dependent decrease in coronary flow, and this effect was more pronounced after hypokinesia. The role of α2-adrenoreceptors in the cardiovascular system under conditions of motor restriction requires further study considering age-related features.
Related Concept Videos
Adrenergic Receptors: ɑ Subtype
Adrenaline ≥ Noradrenaline >> Isoprenaline
α-adrenoceptors are further divided into α1 and α2-adrenoceptors.
α1-Adrenoceptors: These receptors are located postsynaptically on the effector organs and cause constriction of smooth muscle mediated by activation of phospholipase C—inositol-1,4,5-trisphosphate...
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 Receptors (Adrenoceptors): Classification
α-Adrenoceptors
α-Adrenoceptors are classified into two main subtypes: α1 and α2. The α1 adrenoceptors, which are found on postsynaptic...
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...
Sympathetic Signaling
Sympathetic preganglionic fibers release the neurotransmitter acetylcholine (ACh) onto the ganglionic neurons in the...
Adrenergic Antagonists: Pharmacological Actions of β-Receptor Blockers

