J Comp Physiol A (2010) 196:221–226 DOI 10.1007/s00359-010-0507-7 123 ORIGINAL PAPER Intralateral hypothalamic area injection of isoproterenol and propranolol aVects food and water intake in broilers Ali Baghbanzadeh · Mohammad Reza Hajinezhad · Bahram Shohreh · Reza Maleklou Received: 26 June 2009 / Revised: 25 January 2010 / Accepted: 27 January 2010 / Published online: 7 February 2010  Springer-Verlag 2010 Abstract The role played by adrenergic system in water intake, especially food intake, has long been known in mammals. In avian species, there have been many experi- ments exploring the eVects of the adrenergic system in diVerent sites in the central nervous system in meat- and egg-type poultry. This study was designed to examine the possible eVects of intralateral hypothalamic area (ILHy) microinjections of a beta-adrenergic agonist, isoproterenol, and a beta-adrenoceptor blocker, propranolol, on food and water intake in 3-h food-deprived and 3-h water-deprived broiler cockerels. Our Wndings suggest that the -adrener- gic system directly aVects food especially water intake in broilers. Although isoproterenol signiWcantly (P · 0.05) decreased food intake for the Wrst 15 min, it reduced food intake during the experiment. Isoproterenol reduced water intake signiWcantly (P · 0.05), which was abolished by pretreatment with propranolol. It is proposed that -adreno- ceptors in LHy play a direct and indirect role in the regula- tion of food especially water intake in broiler cockerels. Keywords Intralateral hypothalamic area (ILHy) · Isoproterenol · Propranolol · Food intake · Water intake Introduction For many years a dual-center hypothesis was served to explain the neural regulation of food intake in mammals (Stellar 1954). It was based on the work of Hetherington and Ranson (1940), who demonstrated in rats that bilateral lesions of ventromedial hypothalamic nuclei (VMN) resulted in increased food intake and marked obesity. Fur- ther research involving bilateral lesions of the lateral hypo- thalamic area (LHy) resulted in an opposite eVect, complete absence of feeding and drinking, and a marked loss in body weight (Anand and Brobeck 1951). As the knowledge of the neuronal network and their ramiWcations has expanded, the view of functional “centers” has been replaced by that of discrete neuronal populations, expressing speciWc neuro- transmitters that mediate particular eVects on food intake and/or energy expenditure and that are regulated by speciWc signals of nutritional state (Williams et al. 2001). A primary central nervous site for control of energy bal- ance is the hypothalamus. This region is also intimately associated with the regulation of basic functions such as thirst, reproduction, temperature, hormonal balances, and biological rhythms. The hypothalamus consists of more than 40 histologically distinct nuclei and areas, which can be further divided into diVerent subnuclei. Hypothalamic nuclei and areas that are associated with regulation of energy balance include the arcuate, ventromedial, dorsome- dial, paraventricular nuclei, and lateral hypothalamic area. Neurons located in these regions produce chemical messen- gers, which are released at their terminal Welds to stimulate or inhibit feeding behavior (Meister 2007). The hypothalamus is also a major site of food-intake regula- tion in birds. As in mammals, lesioning the ventromedial hypo- thalamus (VMH) of avian species causes hyperphagia, hyperdipsia, and obesity (Kuenzel 1994), whereas lesioning the lateral hypothalamic area decreases food intake. While these sites have traditionally been considered as satiety and feeding centers, respectively, it is currently believed that they are better considered as parts of neural circuits involved in food-intake regulation (Denbow 2000). Kuenzel (1989) A. Baghbanzadeh (&) · M. R. Hajinezhad · B. Shohreh · R. Maleklou Section of Physiology, Department of Basic Sciences, Faculty of Veterinary Medicine, University of Tehran, PO Box 14155-6453, Tehran, Iran e-mail: abaghban@ut.ac.ir