Role of olfactory bulb norepinephrine in the identification and recognition of chemical cues.

In this report the role of olfactory bulb (OB) norepinephrine (NE) in the identification and recognition of urinary chemical cues was examined. In Experiment 1, sexually naive adult male Sprague-Dawley rats were treated with either the noradrenergic neurotoxin, DSP-4, or the water vehicle, and tested for their ability to identify and recognize urinary chemical cues using a habituation-dishabituation paradigm. Treatment with DSP-4 produced an overall decrease in the amount of investigation directed to urine stimuli, with greatest reductions to urine from Zucker females. Overall, DSP-4 treatment did not alter habituation-dishabituation responses. Animals treated with DSP-4 showed a significant reduction in OB-NE, but not dopamine, concentrations. In Experiment 2, hypothalamic catecholamine concentrations and serum samples assayed for testosterone were determined from identically treated animals. Although the NE and dopamine content in MBH was significantly lower in the DSP-4 group, no significant differences in testosterone concentrations were obtained between DSP-4 and controls. These results demonstrate that DSP-4 produces significant reductions in OB-NE and in the amount of investigation directed to urinary chemical cues from females without altering serum testosterone levels. Treatment with DSP-4 treatment does not impair the male rats' ability to demonstrate a habituation-dishabituation response.