Effects of intra-PVN injections of d- and l-norephedrine on feeding in rats.
Phenylpropanolamine (PPA) is thought to inhibit feeding by activation of alpha 1-adrenergic receptors within the paraventricular hypothalamus (PVN). Systemic injections of the PPA component enantiomers, d- and l-norephedrine (NEP), result in differential suppression of feeding (l-NEP more potent than d-NEP). Whether the norephedrine racemates induce differential anorexia subsequent to injection into the PVN is unknown. In the present study, adult male rats received intra-PVN injections of the d- and l-norephedrine enantiomers (0, 80, 160, and 240 nmol). Significantly greater anorexia was obtained for l-NEP relative to d-NEP. These results document a stereospecific effect of the norephedrine enantiomers within the PVN in inhibiting food intake and suggest that the interaction of these enantiomers with PVN alpha 1-adrenoceptors may mediate the similar difference in potency noted for systemic injections of d- and l-norephedrine.
Wellman
P J
PJ
Department of Psychology, Texas A&M University, College Station 77843.
DiCarlo
B
B
Morien
A
A
Davies
B T
BT
D000818:Animals; D000855:Anorexia / Q000139:chemically induced; D004305:Dose-Response Relationship, Drug; D005247:Feeding Behavior / Q000187:drug effects*; D008297:Male; D008845:Microinjections; D009638:Norepinephrine / Q000008:administration & dosage / Q000494:pharmacology*; D010286:Paraventricular Hypothalamic Nucleus / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013237:Stereoisomerism
D009638:Norepinephrine