Fig. 4

Involvement of noradrenergic neurons in diabetic hyperphagia. Effect of bilateral alpha-methyl-p-tyrosine (AMPT), a catecholamine synthesis inhibitor, microimplants in the hypothalamic paraventricular nucleus (PVN) of STZ-induced diabetic rats on food intake (a), body weight (b), and plasma levels of 3HB (c), glucose (d), and NEFA (e) (n = 4 for each group). The open triangles show normal levels of 24-h food intake, body weight, and plasma metabolites for reference. Statistical differences were determined by two-way ANOVA (treatment and day) followed by the Bonferroni test. *P < 0.05, **P < 0.01, versus vehicle-treated controls. Schematic drawings of the placement of the microimplants (f). Open and closed circles show vehicle-treated controls and AMPT-treated rats, respectively. mRNA levels of agouti-related protein (Agrp) and neuropeptide Y (Npy) in the arcuate nucleus (ARC) (g). ARC tissue samples were collected 3 h after injection of pCMBS or vehicle into the 4V. Statistical differences were determined by two-way ANOVA (group and treatment) followed by Student’s t test. *P < 0.05, versus non-diabetic controls. Values are means ± SEM