Preserved olfactory short-term memory after combined cholinergic and serotonergic lesions using 192 IgG-saporin and 5,7-dihydroxytryptamine in rats

Young adult Long-Evans female rats were subjected to intracerebroventricula r injections of 150 mu g 5,7-dihydroxytryptamine (5,7-DHT), 2 mu g 192 IgG- saporin, or a combination of both neurotoxins. All rats were tested for olf actory recognition (short-term memory) using a task based on spontaneous ex ploration of odor sources. Compared with animals undergoing sham operations , 5,7-DHT reduced the concentration of serotonin by 60-80% in the frontopar ietal cortex, hippocampus, striatum and the olfactory bulbs. After 192 IgG- saporin treatment, acetylcholine concentrations were reduced by similar to 40% in all these structures, except the striatum. Neither lesion induced a significant deficit in olfactory recognition. These data suggest that combi ned lesions of cholinergic and serotonergic neurons in the rat brain do not alter olfactory perception or olfactory short-term memory. NeuroReport 11: 347-350 (C) 2000 Lippincott Williams & Wilkins.