Effect of peripheral clonidine on ingestive behavior☆☆☆

An analysis of the effects of systemically administered clonidine on the food and water intake of rats

“…Food intake was increased in the first and second hour after injection and remained above control levels at 6 h. Increases in water intake appeared, in general, to occur at later time periods than increases in food intake and after 0.1 mg/kg water intake remained significantly above control values for 24 h. It has previously been suggested that this long lasting action on drinking may be due to the diuretic effect of clonidine (Atkinson et al, 1978).…”

“…Le Douarec et al (1971,1972) found that clonidine reduced food and water intake in food or water deprived rats. More recently, Atkinson et al (1978) found no increases in food intake at 6 and 24 h after injection in freely feeding rats. It is not clear why the present results differ from those reported by Atkinson et al (1978).…”

“…Also, Leibowitz (1980) found that clonidine can produce a selective increase in carbohydrate intake. In both the present study and that described by Atkinson et al (1978) standard rat diets were used. It is conceivable that these diets differed sufficiently to account for the different effects of clonidine.…”

“…However, there is some controversy as to whether systemically administered clonidine can also enhance either food or water intake. In some studies subcutaneous or oral administration of clonidine has been reported to produce only decreases in eating or drinking (Le Douarec, Schmitt & Lucet, 1971;Atkinson, Kirchertz & Peters-Haefeli, 1978). Mauron, Wurtman & Wurtman (1980), however, reported that intraperitoneal injections of clonidine at doses of 0.025 -0.5 mg/kg caused rats to increase both total food intake and protein intake when they were allowed to select between diets with high or low protein concentrations.…”

The effects of idazoxan and other α2‐adrenoceptor antagonists on food and water intake in the rat

“…Again the mechanism for this response is unknown but it is unlikely to involve indirect activation of fl-adrenoceptors since the 0-agonist isoprenaline reduces urine flow in rats (Lehr et al, 1967). Paradoxically, C2-adrenoceptor agonists also produce diuresis in rats by inhibition of vasopressin secretion in the CNS and its antidiuretic effects in the kidney (Gellai, 1990) which is followed by a secondary increase in drinking (Atkinson et al, 1978;Sanger, 1983).…”