Neonatal olfactory bulbectomy induces anxiety-related behavior and modifies dopaminergic receptor expression in post-pubertal rats

Olfaction is a complex physiological process producing effects in the central nervous system (CNS) and implicated in emotional processes. Indeed, the olfactory bulbs (OB) send projections to various CNS regions including the nucleus accumbens (NAcc) and caudate-putamen (CPu). Both the NAcc and CPu receive important dopaminergic input. Emerging evidence suggests that dopamine (DA) is related to anxiety-related behaviors. Therefore, we aimed to investigate the consequences of neonatal olfactory bulbectomy (nOBX) to anxiety-related behavior as assayed in the elevated plus maze (EPM) as well as the expression of dopaminergic receptors (D1-like, D2-like, and D3) in the NAcc and CPu at pre- and post-pubertal ages in the rat. The results show that nOBX increased the number of entries in the open arm of the EPM post-pubertally, suggesting an anxiolytic-related effect. nOBX increased the D2-like binding in the NAcc shell and D3 binding in the NAcc core pre-pubertally. At post-pubertal ages, the D3 binding was reduced at the olfactory tubercle and islands of Calleja in nOBX rats. Alterations in the DA receptor expression may be one mechanism responsible for the observed behavioral modifications in nOBX rats.

Automated summary

Olfaction is a complex physiological process that affects the central nervous system and is involved in emotional processes. The olfactory bulbs in rats are connected to various regions of the central nervous system, such as the nucleus accumbens and caudate-putamen, which receive important dopaminergic input. Dopamine has been found to be related to anxiety-related behaviors. This study investigated the effects of neonatal olfactory bulbectomy on anxiety-related behavior in rats using the elevated plus maze, as well as the expression of dopaminergic receptors in the nucleus accumbens and caudate-putamen. The results showed that neonatal olfactory bulbectomy increased open arm entries in the elevated plus maze in post-pubertal rats, indicating an anxiolytic effect. The expression of D2-like binding in the nucleus accumbens shell and D3 binding in the nucleus accumbens core increased in pre-pubertal rats after olfactory bulbectomy. However, D3 binding was reduced in the olfactory tubercle and islands of Calleja in olfactory bulbectomized rats at post-pubertal ages. These findings suggest that alterations in dopaminergic receptor expression may contribute to the observed behavioral changes in olfactory bulbectomized rats.