Related Experiment Video
Updated: Aug 14, 2026

Measurement of Smooth Muscle Function in the Isolated Tissue Bath-applications to Pharmacology Research
Published on: January 19, 2015
[Experimental study of the biological activities of several alpha1-adrenoceptor antagonists in vitro]
1School of Pharmacy, Nanjing Medical University, Nanjing, Jiangsu 210029, China. wubin@njmu.edu.cn
Objective:
To study the biological activities of several alpha1-adrenoceptor antagonists in vitro.
Methods:
The anococcygeal muscle from male Sprague-Dawley rats (300-350 g) was isolated, removed and suspended in a 20-ml organ chamber containing Krebs solution at 37 degrees C, pH 7.4. The muscle preparations were set at a resting tension of 1.0 g and allowed to equilibrate for 1 h in the Krebs solution. After thorough washing, the anococcygeal muscle preparations were examined for the effects of the tested compounds with increased concentrations on its contractile/relaxant responses and the pA2 of antagonistic activity was assessed.
Results:
Some of the target compounds displayed blocking activity to alpha1-adrenoceptor.
Conclusion:
Compounds WB IV-1 and WB IV-3 showed good inhibiting activity, and were worth further studying.
More Related Videos
Related Concept Videos
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 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 Agonists: Chemistry and Structure-Activity Relationship
Aromatic ring substitutions: Substituting the aromatic ring with –OH groups at positions 3 and 4 yields catecholamines (e.g., epinephrine), which have a high affinity for adrenoceptors. Hydrogen bonding between –OH groups and receptors enhances adrenergic activity.
Separation of the aromatic...
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...

