Ionic effects of capsinolol, a calcitonin gene-related peptide releasing beta-adrenoceptor blocker, on isolated cardiac muscles.
1. Capsinolol (1.0-30.0 microM) in a cumulating manner decreased the maximum upstroke velocity (Vmax), the action potential amplitude and twitch tension in isolated guinea-pig atria and papillary muscle, rabbit papillary muscle, dog Purkinje fibers and human ventricle tissues. 2. In the isolated guinea-pig atrium, perfusing with capsinolol at 3 microM for 3 min temporarily increased the twitch force and decreased spontaneous cycle length; however, the results were reversed after longer exposure of the tissue. 3. Capsinolol prolonged the duration of action potential in the guinea-pig atrium and rabbit papillary muscles. The maximum diastolic potential was shifted to a less-negative level in dog Purkinje fibers and human ventricular muscles.
Department of Pharmacology, Graduate Institute of Medicine, Kaohsiung Medical College, Taiwan, Republic of China.
J L
JL
Yeh
J R
JR
Wu
C I
CI
Lin
I J
IJ
Chen
D000200:Action Potentials / Q000187:drug effects; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism*; D002211:Capsaicin / Q000031:analogs & derivatives* / Q000494:pharmacology; D004285:Dogs; D006168:Guinea Pigs; D006321:Heart / Q000187:drug effects*; D006352:Heart Ventricles / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D007477:Ions; D008297:Male; D009206:Myocardium / Q000378:metabolism; D010210:Papillary Muscles / Q000187:drug effects / Q000378:metabolism; D011690:Purkinje Fibers / Q000187:drug effects / Q000378:metabolism; D011817:Rabbits; D013045:Species Specificity
D000319:Adrenergic beta-Antagonists; D007477:Ions; C104667:capsinolol; D015740:Calcitonin Gene-Related Peptide; D002211:Capsaicin