Pharmacology of smooth muscle

 

All smooth muscles can be made to relax (or sometimes contract) by use of drugs. In medical vagotomy, anticholinergic drugs (such drugs like atropine or atropine -like drugs) are given to block the parasympathetic system of the vagus nerve to the gut since this system is mainly cholinergic (i.e. acetylcholine is its neurotransmitter). They are called parasympatholytic drugs, while acetylcholine is said to be parasympathomimetic or cholinomimetic drug. Such anticholinergic drugs cause relaxation in the gut etc. and are used to relieve colicky abdominal pain. Sympathomimetic drugs (catecolamines) also cause relaxation of the bronchial tree and this is means by which asthma (which is bronchospasm) or its severe variety status asthmaticus, can be treated.

Drugs acting on muscle receptors

bullet

α1 agonists include norepinephrine, and many imidazolines such as xylometazoline, are vasoconstrictors.

bullet

α2 agents  act on the central nervous system, e.g. clonidine.

bullet

β1 used for cardiac inotropic effect, e.g. dobutamine.

bullet

β2 agents are bronchodilators or myometrial relaxants  and this includes salbutamol, terbutaline, fenoterol, pirbuterol and ritodrine

 

 

There is nothing in anatomy not found in this website

Electronic School of Medicine
Creator: Oluwole Ogunranti

          


Smooth muscle of  human fallopian tube showing smooth muscles in isthmus

 

 

 

 

 

Introduction

Histology

   Smooth muscle

   Striated muscle

   Cardiac muscle

Embryology
Gross anatomy
Organ integration
Clinical anatomy

Quiz

Physiology

Smooth muscle      

Striated muscle      

Cardiac muscle      

Biochemistry

Pharmacology
Smooth muscle      

Striated muscle    

Cardiac muscle      

Chemical Pathology

Anatomical Pathology

Imaging

Medicine

Surgery

Main Subject Course Links

eAnatomy eAnesthesia eBiochemistry eChemical pathology eCommunity Health
eDermatology eENT eGynecology eHematology eImaging
eMedicine eMedical microbiology eObstetrics eOphthalmology ePathology
ePediatrics ePharmacology ePhysiology ePsychiatry    eSurgery/eOrthopedics
eLab eOSCE eProcedures eInvestigations eSchool/Videopage
eOrgans eLocator Anatomy Museum eDissector eFractures/Dissect-it-yourself
All diseases eClerking eTreatment eDoctor ePatient