Altered thermoregulatory responses to clonidine in streptozotocin‐diabetic rats

Abstract

temperature occurred in control rats given clonidine challenge (0.05-2.0 mg kg-', s.c.); this response was inhibited by prior administration of either yohimbine or idazoxan (2 mg kg-1, s.c.) but not by the peripherally-acting a2-adrenoceptor antagonist L-659,066(10 mg kg-', s.c.).3 In rats treated with STZ (65 mg kg-', i.v.) administration of clonidine elicited a dose-independent hyperthermia (circa 1°C.); this effect was unaltered by prior administration of yohimbine or idazoxan. 4 Naloxone (5 mg kg-', s.c.) elicited a small fall in temperature(< 1°C.) in both control and STZtreated rats; naloxone pretreatment did not alter the temperature response to clonidine in either group. 5 Nicotinic acid (10 mg kg-', s.c.) caused a similar small elevation in temperature in both groups. 6 Administration of replacement insulin to STZ-treated rats maintained weight gain and low blood glucose while the thermoregulatory response to clonidine slowly reverted to normal. 7 These results show that altered central temperature control is an element of the generalised abnormality of a2 receptor function induced by STZ.

Food restriction and streptozotocin differentially modify sensitivity to the hypothermic effects of direct- and indirect-acting serotonin receptor agonists in rats

“…Using telemetry studies in rats, it has been reported that streptozotocin decreases resting core temperature by 0.4° C (Howarth et al, 2005). Moreover, compared with untreated rats, diabetic rats are less sensitive to clonidine-induced hypothermia and more sensitive to apomorphine-induced hypothermia (O’Donnell et al, 1996; Bjorenson and Quock, 1988). In the current study, streptozotocin did not significantly alter body temperature, perhaps because of procedural differences between the two studies (current study versus Howarth et al, 2005, respectively): 7 versus 10 days after streptozotocin; 50 versus 60 mg/kg of streptozotocin; rectal probe versus telemetry; Sprague Dawley versus Wistar rats; testing in a separate procedure room versus in the home cage.…”

Modulation of MK-801-induced behaviour by noradrenergic agents in mice

“…The dose of yohimbine was chosen based on its ability to antagonize the hypothermic response to clonidine, a model of central α 2 -adrenoceptor function (O'Donnell et al 1996).…”

Comparison of the Effects of Selective III, IV and Nonselective Phosphodiesterase Inhibitors on Isolated Tracheal Preparations in Streptozotocin-Diabetic Rats

“…It has been reported that PDE enzyme activity may be altered in diseases such as diabetes mellitus, hypertension, hyperthyroidism and hypothyroidism [8,9]. For example, diabetes mellitus is associated with high levels of cAMP in tissue and plasma [6].…”