Diabetes mellitus-and cooling-induced bladder contraction: An in vitro study

Abstract

The effects of diabetes mellitus during cooling on ACh-and KCl-induced responses were investigated in rat urinary bladder. Diabetes was induced in the rats by 50 mg/kg streptozotocin via an intraperitoneal injection. Rats' body and bladder weights were measured. The isometric tension to ACh (10-9 -3 × 10-4 M) and KCl (5-100 mM) in strips of urinary detrusor muscle of diabetic and non-diabetic rats, in organ baths at 37 and 28°C were recorded. The body weights were significantly decreased and the bladder weights increased in STZ-induced diabetic group compared to the non-diabetic group. ACh and KCl caused concentration-dependent contractions of urinary bladders from non-diabetic and STZ-induced diabetic rats. During cooling, the sensitivity and the maximal response were significantly higher than those during 37°C, both in non-diabetic and diabetic preparations. Cooling of detrusor muscle preparations induces a graded contraction inversely proportional to the temperature in diabetic rats. It may be assumed that the cooling response involves the same mechanisms in the diabetic and non-diabetic animals.