Neonatal 6-hydroxydopa alters conspecific odor investigation by male rats

Abstract

Odor-guided behavior was examind in male rats injected at birth and 48 h later with either the catecholaminergic neurotoxin 6-hydroxydopamine (60 μg/g, i.p.) or vehicle. In odor preference tests administered 8 or 74 days postnatally, drug-treated animals avoided novel odors which were neutral for controls and showed reduced preference for conspecific nest odors. In emergence tests administered 73–75 days postnatally, odors from an anesthetized female reduced approach latency and increased investigation of familiar conspecific odors for control but not drug-treated males. Neonatal drug treatment decreased adult olfactory cortex norepinephrine (NE) levels by 50%, but did not significantly influence either cardiac NE or olfactory cortex dopamine. The results imply that brain NE facilitates attraction to familiar conspecific odors.