Related Experiment Video
Updated: Aug 16, 2026

Fentanyl Analog Screening using LC-TIMS-TOF MS/MS
Published on: November 8, 2024
Fentanyl attenuates alpha1B-adrenoceptor-mediated pulmonary artery contraction
Ju-Tae Sohn1, Xueqin Ding, Daniel F McCune
1Department of Anesthesia and Pain Medicine, Institute of Health Sciences, College of Medicine, Gyeongsang National University, Jinju, Republic of Korea.
Background:
The authors tested the hypothesis that the intravenous anesthetic fentanyl would attenuate the pulmonary vasoconstrictor response to alpha1-adrenoceptor activation. They also investigated the alpha1-adrenoceptor subtypes that could potentially mediate this effect of fentanyl.
Methods:
Endothelium-denuded canine pulmonary arterial rings were suspended for isometric tension recording. Dose-response curves for the alpha1-adrenoceptor agonist phenylephrine were generated in the absence and presence of fentanyl. The effects of inhibiting alpha2 (rauwolscine), alpha1 (prazosin), alpha1A (5-methylurapidil), alpha1B (chloroethylclonidine), and alpha1D (BMY 7378) adrenoceptors on phenylephrine contraction were also investigated. Receptor "protection" studies were performed to investigate the specific role of alpha1B adrenoceptors in mediating fentanyl-induced changes in phenylephrine contraction. Finally, competition binding studies were performed in rat-1 fibroblasts stably transfected with human alpha1-adrenoceptor complementary DNAs corresponding to the alpha1A-, alpha1B-, or alpha1D-adrenoceptor subtypes to directly assess whether fentanyl can compete for the alpha1-adrenoceptor activation pocket.
Results:
Fentanyl attenuated phenylephrine contraction in a dose-dependent fashion. Rauwolscine had no effect on phenylephrine contraction. Phenylephrine contraction was inhibited by prazosin and abolished by chloroethylclonidine but was relatively resistant to inhibition by 5-methylurapidil and BMY 7378. Pretreatment with fentanyl before exposure to chloroethylclonidine increased the maximal contractile response to phenylephrine compared to chloroethylclonidine pretreatment alone. Competition binding studies revealed that fentanyl binds to all three alpha1-adrenoceptor subtypes, with a fivefold greater affinity for the alpha1B-adrenoceptor compared with the alpha1D-adrenoceptor subtype.
Conclusion:
Phenylephrine-induced contraction is primarily mediated by alpha1B-adrenoceptor activation in canine pulmonary artery. Fentanyl attenuates phenylephrine contraction by binding to alpha1B adrenoceptors.
Related Concept Videos
Opioid Analgesics: Synthetic and Semisynthetic Opioids
Adrenergic Antagonists: ɑ and β-Receptor Blockers
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...
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 Antagonists: Pharmacological Actions of β-Receptor Blockers
Treatment for Pulmonary Arterial Hypertension: Endothelin Receptor Antagonists
ETs are synthesized through a complex sequence of enzymatic steps, primarily involving an enzyme referred to as endothelin-converting enzyme (ECE). Of...
