title: Methylxanthines and ryanodine receptor channels.
abstract: Methylxanthines of either natural or synthetic origin have a number of interesting pharmacological features. Proposed mechanisms of methylxanthine-induced pharmacological effects include competitive antagonism of G-coupled adenosine A(1) and A(2A) receptors and inhibition of phosphodiesterases. A number of studies have indicated that methylxanthines also exert effects through alternative mechanisms, in particular via activation of sarcoplasmic reticulum or endoplasmic reticulum ryanodine receptor (RyR) channels. More specifically, RyR channel activation by methylxanthines was reported (1) to stimulate the process of excitation coupling in muscle cells, (2) to augment the excitability of neurons and thus their capacity to release neurotransmitters, and also (3) to improve their survival. Here, we address the mechanisms by which methylxanthines control RyR activation and we consider the pharmacological consequences of this activation, in muscle and neuronal cells.
authors.affiliation: Centre de Recherche de l'Institut du Cerveau et de la Moelle Epinière, Université Pierre et Marie Curie-Paris 6, Paris, France.
authors.forename: Serge
authors.initials: S
authors.lastname: Guerreiro
authors.forename: Marc
authors.initials: M
authors.lastname: Marien
authors.forename: Patrick P
authors.initials: PP
authors.lastname: Michel
mesh_terms: D000818:Animals; D002110:Caffeine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D009119:Muscle Contraction / Q000187:drug effects; D009474:Neurons / Q000187:drug effects; D018377:Neurotransmitter Agents / Q000378:metabolism; D019837:Ryanodine Receptor Calcium Release Channel / Q000187:drug effects* / Q000502:physiology; D014970:Xanthines / Q000494:pharmacology*
chemical_list: D018377:Neurotransmitter Agents; D019837:Ryanodine Receptor Calcium Release Channel; D014970:Xanthines; C008514:methylxanthine; D002110:Caffeine; D002118:Calcium