Olfactory system involvement in the recovery of feeding and drinking after lateral hypothalamic damage in the rat

In rats, large lesions of the far lateral hypothalamus produce a familiar syndrome of behavioral deficits which include the absence of feeding and drinking. If tube fed and offered palatable food LH lesioned rats gradually recover and eventually become able to maintain a stable body weight on dry food and water. In this series of experiments we show that although bilateral removal of the olfactory bulbs does not affect a rat's ability to feed and drink to maintain a normal body weight (Experiment 1), bulbectomy performed about one month prior to lateral hypothalamic lesioning can seriously jeopardize the recovery of feeding and drinking after lateral hypothalamic damage (Experiment 2). Additionally (Experiment 3), in some recovered lateral hypothalamically lesioned rats bulbectomy is followed by a period of persistent adipsia and anorexia from which recovery nevertheless occurs. Thus, although the olfactory bulbs may make a contribution to the maintenance of drinking and feeding in the recovered LH rat, this contribution is apparently not an indispensible one.