Expression of dopamine receptors in rat olfactory bulb and its role in hyposmia of Parkinson' s disease rat model / 解剖学报

ABSTRACT

Objective: To observe the localization and expression of dopamine receptors in olfactory bulb (OB) of rats and explore the effect of L-levodopa (L-DOPA) treatment on hyposmia in Parkinson' s disease (PD) rat model. Methods: Western blotting, immunohistochemistry and immunofluorescence were used to observe the expression and localization of dopamine receptors in the OB. PD rat model was established by bilateral 6-hydroxy dropamine(6-OHDA) injection to detect the effect of L-DOPA treatment on the hyposmia and the expression of glutamic decarboxylase (GAD) and brain derived neurotrophic factor (BNDF) of PD rats. Results Dl and D2 receptors were the major subtypes in the OB.D1 and D2 receptors were expressed by GAD positive Î3-aminobutyric acid (GABA) ergic neurons in the granule cell layer(GCL) which surrounded by tyrosine hydroxylase (TH) positive nerve fibers. The expression of TH in the GCL layer of PD rats decreased significantly (0. 05±0. 01 vs 0. 01±0. 00,P<0. 001). After L-DOPA treatment, the time of finding food balls in PD rats was significantly reduced [(624. 4±113.4)s vs (312. 4±79. 35) s, P<0.05]and the expression of BDNF in the OB was increased (0. 02±0. 01 vs 0. 07±0. 01, P<0. 01). Conclusion Dl and D2 are expressed in the GABAergic neurons in the GCL layer of OB. L-DOPA treatment alleviates the hyposmia of PD rats, which may be related to the D1-D2 receptor heteromeractivation and its downstream BDNF expression of GABAergic neurons.