Chronic infusion of norepinephrine and clonidine into the hypothalamic paraventricular nucleus.
Previous experiments have shown that acute injection of NE and CLON into the PVN initiates a short-term feeding response in satiated rats. This study examined, in brain-cannulated rats, the impact of remote, chronic injections of NE, CLON, or saline on daily food intake and body weight gain. Over a period of 14 days, NE was infused into the PVN, either continuously at a rate of 12 nm/microliter/hr, or discretely at a rate of 6 nm/microliter/sec. In addition, the alpha 2-adrenergic agonist CLON was infused into the PVN discretely at a rate of 3 nm/0.5 microliter/30 sec. Relative to saline infusion, chronic (continuous or discrete) stimulation of the PVN with either of these drugs was effective in potentiating daily food intake by 12-19% and in increasing body weight gain, from approximately 1.5 g/day to 3.3 g/day. This evidence indicates that medial hypothalamic NE, especially within the PVN, is sufficiently robust to alter long-term feeding patterns and body weight regulation.
D000818:Animals; D001835:Body Weight / Q000187:drug effects; D003000:Clonidine / Q000494:pharmacology*; D004326:Drinking / Q000187:drug effects; D004435:Eating / Q000187:drug effects*; D007031:Hypothalamus / Q000187:drug effects; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains
D003000:Clonidine; D009638:Norepinephrine