Smooth Muscle Flashcards
What G-coupled protein promotes Calcium release and smooth muscle contraction?
Gq - IP3 secondary messenger
What does Gs coupled receptor do to smooth muscle?
Inhibits contraction due to reduction of Ca+2
What drug is a venous dominant dilator and how does it work?
Nitroglycerin. Acts like NO, increasing cGMP causing relaxation of smooth muscle and vasodilation.
What nitroxide derivative affects both arterial and venous vessels and can be used for HTN emergencies?
Nitroprusside
Used to treat heart failure and HTN Emergencies. Direct Arterial dilator. Decreases Afterload.
Hydralazine and Minoxidil
What drug promotes hair growth/prevents and can cause fluid retention.
Minoxidil. Arterial dilator, helps with capillary at the hair roots.
What drug causes K+ channel depolarization and inhibits insulin release from the pancreas?
Diazoxide. Used for HTN emergencies.
What effects do Phosphodiesterase inhibitors have on cardiac muscle?
PDE3 (found in cardiac muscle) prevents breakdown of cAMP allowing more flux of Ca+2 and increased force/velocity of contraction. [Some PDE3 are in smooth muscle too, which can cause relaxation]
What effect does a phosphodiesterase inhibitor do in smooth muscle?
Prevents the cGMP breakdown, causing relaxation of smooth muscle.
What drugs are used for erectile dysfunction?
Sildenafil and Tadalafil
What are the three PDE3 inhibitors used for CHF?
Milrinone, Inamrinone, and Cilostazol (increases contractile force of the heart)
What dopamine receptor agonist is used for increased renal blood flow and increased sodium excretion?
Fenoldopam. Decreases both preload and afterload.
How does Prazosin work?
A1 Antagonist to cause vasodilation in the endothelium both arterial and venous.
What are the B2 agonists for broncodilation and what is the number one side effect?
Side Effect is Tachycardia. Albuterol, Pirbuterol, Terbutaline, Salmeterol, and Formoterol
What are the anti-cholinergic broncodilators?
Ipratropium and Tiotropium
What is an Adenosine antagonsit?
Theophylline prevents bronchoconstriction by inhibiting adenosine (anti-inflammatory factor)
What are the two functions of Theophylline?
PDE3 Inhibitor and Adenosine antagonist. Prevents breakdown of cAMP, causing extended relaxation of the smooth muscle and prevents adenosine from broncoconstriction
What is the other drug with same mechanism of Theophylline?
Aminophylline
