Microanatomical localization of dopamine receptor protein immunoreactivityin the rat cerebellar cortex

Dopamine (DA) receptor subtype localization was investigated in wt cerebell ar cortex using immunohistochemical techniques with antibodies raised again st D1-D5 receptor protein. A faint DI receptor protein immunoreactivity was developed in molecular and Purkinje neurons layers. D2 receptor protein im munoreactivity was found primarily in cerebellar white matter followed by m olecular and granular layers and Purkinje neurons. Antibodies against D2S r eceptor protein were localized in molecular Layer and to a lesser extent, i n granular layer. A few Purkinje neurons displayed a faint D2S receptor pro tein immunoreactivity. D3 receptor protein immunoreactivity was observed pr imarily in molecular and in Purkinje neurons layers of lobules 9 and 10. A faint D3 receptor protein immunoreactivity was also localized in Purkinje n eurons and to a lesser extent, in molecular and granular layers of cerebell ar lobules 1-8. D4 receptor protein immunoreactivity was found in cerebella r white matter. A pale immunostaining was also visualized in molecular laye r. D5 receptor protein immunoreactivity was localized primarily in molecula r and Purkinje neurons layers and to a lesser extent, in granular layer and in white matter. The above results indicate that wt cerebellar cortex expr esses the DA receptor subtypes so far identified. Purkinje neurons, which a re the only efferent neurons of cerebellum, are richest in DA receptor prot ein immunoreactivity. This suggests that dopaminergic neurotransmission may modulate efferent inputs from cerebellum The localization of the majority of D2 and D4 and of a faint D5 protein receptor immunoreactivity in cerebel lar white matter suggests that these receptors may be presynaptic and trans ported axonally. (C) 2000 Elsevier Science B.V. All rights reserved.