QUANTITATIVE AUTORADIOGRAPHIC STUDIES OF THE EFFECTS OF BILATERAL OLFACTORY BULBECTOMY IN THE RAT-BRAIN - CENTRAL-TYPE AND PERIPHERAL-TYPE BENZODIAZEPINE RECEPTORS
V. Beauchemin et al., QUANTITATIVE AUTORADIOGRAPHIC STUDIES OF THE EFFECTS OF BILATERAL OLFACTORY BULBECTOMY IN THE RAT-BRAIN - CENTRAL-TYPE AND PERIPHERAL-TYPE BENZODIAZEPINE RECEPTORS, Neuroscience, 58(3), 1994, pp. 527-537
We investigated the discrete regional effects of bilateral olfactory b
ulbectomy on central- and peripheral-type benzodiazepine receptors in
rat brains at weekly intervals until one month after bulb ablation. Pe
rsistent increases in [H-3]flunitrazepam binding to central benzodiaze
pine receptors were observed in the cingulum (27%) and in the frontal(
15%) and parietal (14%) cortices. Progressive increases in central ben
zodiazepine receptors, reaching statistical significance four weeks af
ter olfactory bulbectomy, were observed in the ventromedial thalamic n
ucleus (35%), the lateral hypothalamic region (22%), the basolateral a
mygdaloid nucleus (23%) and substantia nigra (25%). Persistent major i
ncreases (between four- and six-fold) in [H-3]PK-11195 phenyl)-N-methy
l-N-(1-methylpropyl)-3-isoquinoline carboxamide binding to peripheral-
type benzodiazepine receptors were observed in all anterior olfactory
nuclei. Similarly, throughout the time period studied, [H-3]PK-11195 b
inding densities were increased two- to three-fold in the piriform cor
tex and lateral olfactory tract. These observations confirm the useful
ness of [H-3]PK-11195 binding as a marker of neuronal insult in the br
ain. Moreover, the persistent regional increases in [H-3]flunitrazepam
binding to central-type benzodiazepine receptors suggest that GABAerg
ic transmission is altered following olfactory bulb ablation.