Neonatal olfactory bulbectomy enhances locomotor activity, exploratory behavior and binding of NMDA receptors in pre-pubertal rats

Neuroscience. 2014 Feb 14;259:84-93. doi: 10.1016/j.neuroscience.2013.11.047. Epub 2013 Dec 1.

Abstract

In this study, we investigated the effect of neonatal olfactory bulbectomy (nOBX) on behavioral paradigms related to olfaction such as exploratory behavior, locomotor activity in a novel environment and social interaction. We also studied the effect of nOBX on the activity of the N-methyl-d-aspartate (NMDA) subtype of glutamate receptors during development. The behavioral effects of nOBX (postnatal day 7, PD7) were investigated in pre- (PD30) and post-pubertal (PD60) Wistar rats. NMDA receptor activity was measured with [(125)I]MK-801 in the brain regions associated with the olfactory circuitry. A significant increase in the novelty-induced locomotion was seen in the pre-pubertal nOBX rats. Although the locomotor effect was less marked than in pre-pubertal rats, the nOBX rats tested post-pubertally failed to habituate to the novel situation as quickly as the sham- and normal- controls. Pre-pubertally, the head-dipping behavior was enhanced in nOBX rats compared with sham-operated and normal controls, while normal exploratory behavior was observed between groups in adulthood. In contrast, social interaction was increased in post-pubertal animals that underwent nOBX. Both pre- and post-pubertal nOBX rats recovered olfaction. Interestingly, pre-pubertal rats showed a significant increase in the [(125)I]MK-801 binding in the piriform cortex, dorsal hippocampus, inner and outer layers of the frontal cortex and outer layer of the cingulate cortex. At post-pubertal age, no significant differences in [(125)I]MK-801 binding were observed between groups at any of the brain regions analyzed. These results suggest that nOBX produces pre-pubertal behavioral disturbances and NMDA receptor changes that are transitory with recovery of olfaction early in adulthood.

Keywords: ANOVA; BL; Cg; DG; EDTA; HBT; MK-801; N-methyl-d-aspartate; NAcc; NMDA; NMDA receptor; OBX; OF; OT; PBS; PD; PFC; RMS; SI; SVZ; ablation of the olfactory bulbs; analysis of variance; basolateral; cingulate cortex; dPFC; dentate gyrus; dizocilpine; dorsal part of the prefrontal cortex; ethylenediaminetetraacetic acid; hole board test; limbic system; locomotion; nOBX; neonatal ablation of the olfactory bulbs; neonatal bilateral ablation of the olfactory bulbs; nucleus accumbens; olfactory bulbectomy and depression; olfactory tubercle; open field; phosphate saline solution; postnatal day; prefrontal cortex; rostral migratory stream; social interaction; subventricular zone.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Age Factors
  • Animals
  • Animals, Newborn
  • Dizocilpine Maleate / pharmacokinetics
  • Exploratory Behavior / physiology*
  • Female
  • Interpersonal Relations
  • Iodine Radioisotopes / pharmacokinetics
  • Male
  • Motor Activity / physiology*
  • Olfactory Bulb / growth & development
  • Olfactory Bulb / physiology*
  • Olfactory Bulb / surgery
  • Olfactory Pathways
  • Pregnancy
  • Protein Binding / physiology
  • Radioligand Assay
  • Rats
  • Rats, Wistar
  • Reaction Time / physiology
  • Receptors, N-Methyl-D-Aspartate / metabolism*
  • Smell / physiology*
  • Statistics, Nonparametric
  • Time Factors

Substances

  • Iodine Radioisotopes
  • Receptors, N-Methyl-D-Aspartate
  • Dizocilpine Maleate