Methylxanthines exe the following action(s) at cellular/molecular level:
Methyl xanthines include :of- Theophylline, aminophylline, Choline theophyllinate etc.. Mech of action of methylxanthines:- (a) Release of Ca2+ from sarcoplasmic reticulum, especially in skeletal and cardiac muscle. (b) Inhibition of phosphodiesterase (PDE) which degrades cyclic nucleotides i(cAMP, CGMP etc..) thus increasing their concentration. Bronchodilatation, cardiac stimulation and vasodilatation occur when cAMP level rises in the concerned cells. (c) Blockade of adenosine receptors: adenosine acts as a local mediator in CNS, CVS and other organs--contracts smooth muscles, especially bronchial; dilates cerebral blood vessels, depresses cardiac pacemaker and inhibits gastric secretion. Ref:- kd tripathi; pg num:- 225,226
Intracellular release of Ca2+
Inhibition of phosphodiesterase
Antagonism of adenosine
All of the above
Respiratory system