The effect of beta 2-adrenoceptor stimulation and blockade of L-type calcium channels on in vivo Na+/H+ antiporter activity in rat skeletal muscle.
We have studied the in vivo response of the Na+/H+ antiporter in skeletal muscle to beta 2-adrenoceptor stimulation with isoprenaline and the effect of blocking L-type calcium channels with nifedipine. Na+/H+ antiporter activity in skeletal muscle in vivo increased after beta 2-adrenoceptor stimulation with isoprenaline; nifedipine attenuated that effect. This suggests that opening of L-type calcium channels is necessary for full activation of the Na+/H+ antiporter in skeletal muscle. Bleeding also increased Na/H+ antiporter activity, which we believe could be explained by an increase in sympathetic nervous system activity as a result of hypotension. This may be one of the mechanisms by which animals under stress prepare their skeletal muscle for exercise as part of the 'fright and flight' reaction.
Syme
P D
PD
University Department of Clinical Pharmacology, Radcliffe Infirmary, Oxford, U.K.
Brunotte
F
F
Green
Y
Y
Aronson
J K
JK
Radda
G K
GK
D000255:Adenosine Triphosphate / Q000378:metabolism; D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007545:Isoproterenol / Q000494:pharmacology; D007773:Lactates / Q000378:metabolism; D008297:Male; D009119:Muscle Contraction; D009132:Muscles / Q000187:drug effects / Q000378:metabolism*; D009543:Nifedipine / Q000494:pharmacology; D010710:Phosphates / Q000378:metabolism; D010725:Phosphocreatine / Q000378:metabolism; D051381:Rats; D011921:Rats, Inbred WKY; D011943:Receptors, Adrenergic, beta / Q000187:drug effects / Q000378:metabolism*; D017923:Sodium-Hydrogen Exchangers
D002121:Calcium Channel Blockers; D015220:Calcium Channels; D002352:Carrier Proteins; D007773:Lactates; D010710:Phosphates; D011943:Receptors, Adrenergic, beta; D017923:Sodium-Hydrogen Exchangers; D010725:Phosphocreatine; D000584:Amiloride; D000255:Adenosine Triphosphate; D009543:Nifedipine; D007545:Isoproterenol