<prompt> Methylxanthines exe the following actions at cellularmolecular level:Intracellular release of Ca2Inhibition of phosphodiesteraseAntagonism of adenosineAll of the above  <response>: 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 icAMP, 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 