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β‐Adrenoreceptors in denervated skeletal muscles of the cat
Author(s) -
Bohmer K.,
Raper C.
Publication year - 1975
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1111/j.1440-1681.1975.tb03029.x
Subject(s) - orciprenaline , practolol , chronotropic , isoprenaline , medicine , soleus muscle , skeletal muscle , endocrinology , cats , agonist , stimulation , salbutamol , chemistry , propranolol , heart rate , receptor , blood pressure , asthma
SUMMARY1 A number of sympathomimetic amines have been compared with (‐)‐iso‐prenaline for their ability to produce contractions in chronically denervated soleus and tibialis anterior muscles and to increase heart rate in bilaterally vagotomized anaesthetized cats. 2 The mean dose‐ratios ((‐)‐isoprenaline = 1) for adrenaline, orciprenaline and salbutamol were 2.9, 29.7 and 11.5 respectively in the tibialis anterior muscle and 3.5, 24–1 and 14.3 in the soleus muscle. The dose‐ratios for noradrenaline were 21.1 in the tibialis anterior and 57.6 in the soleus muscle. 3 The dose‐ratios ((‐)‐isoprenaline = 1) obtained for the positive chronotropic effects of the drugs in bilaterally vagotomized cats were 14.5, 14.6, 29–6 and 24.2 for adrenaline, noradrenaline, orciprenaline and salbutamol respectively. 4 The β 2 ‐receptor antagonists butoxamine and H35/25 antagonized the vaso‐depressor and skeletal muscle responses to (‐)‐isoprenaline to a greater extent than the cardiac responses, whereas the β 1 ‐receptor selective antagonists practolol and H93/26 antagonized cardiac to a greater extent than vascular and skeletal muscle responses. 5 The results obtained suggest that the contractions of denervated skeletal muscle to sympathomimetic drugs result from stimulation of β 2 ‐adrenoreceptors.