Ca(2+)-channels and adrenoceptors in diabetic skeletal muscle.
The status of Ca(2+)-channels and adrenoceptors in the hind leg skeletal muscle was examined in rats 8 weeks after inducing diabetes by an intravenous injection of streptozotocin (65 mg/kg). Scatchard plot analysis of the data on specific binding of 3H-nitrendipine with crude membranes from diabetic muscle revealed an increase in the density of Ca(2+)-channels without any significant change in their affinity for the ligand. An increase in the density of beta-adrenoceptors without any alteration in their affinity, as measured by 3H-dihydroalprenolol binding, was also evident in the diabetic muscle. The observed increase in the number of Ca2+ channels or beta-adrenoceptors seems specific since no change in the alpha-adrenoceptor density or affinity, as measured by 3H-prazosin binding, was seen in the diabetic membranes. These results support the view that higher activities of Ca2+ transport systems or regulatory mechanisms may be associated with hyperfunction of the diabetic skeletal muscle.
Lee
S L
SL
Division of Cardiovascular Sciences, St. Boniface General Hospital Research Centre, University of Manitoba, Winnipeg, Canada.
Dhalla
N S
NS
D000818:Animals; D015220:Calcium Channels / Q000378:metabolism*; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D004082:Dihydroalprenolol / Q000378:metabolism; D007700:Kinetics; D008297:Male; D009132:Muscles / Q000378:metabolism*; D009568:Nitrendipine / Q000378:metabolism; D011224:Prazosin / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D011942:Receptors, Adrenergic, alpha / Q000378:metabolism; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*; D012016:Reference Values
D015220:Calcium Channels; D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta; D004082:Dihydroalprenolol; D009568:Nitrendipine; D011224:Prazosin