Exp Neurobiol 2003; 12(1): 33-42
Published online July 1, 2003
© The Korean Society for Brain and Neural Sciences
Gyeong Jae Cho, Sang Soo Kang, Ji-Myong Yoo1 and Wan Sung Choi1,*
Departments of Anatomy and Neurobiology and 1Ophthalmology, College of Medicine, Gyeongsang National University, Jinju 660-751, Korea
Correspondence to: *To whom correspondence should be addressed.
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Dopamine is a major neurotransmitter detected in mammalian retina. In the retina, dopamine performs various physiological and pharmacological roles that are mediated by several receptor subtypes. Although many reports have focused on the localization and functions of dopamine receptor subtypes in the retina, they have not been elucidated clearly yet. In this study, we report about the spatial distribution and expression pattern of dopamine D1 and D2 receptor mRNAs according to developmental stages in foetal rhesus monkey retina. We have determined mRNA quantities of dopamine receptor subtypes by RNase Protection Assay (RPA). Their localization in retinal tissue was confirmed using in situ hybridization. Our results show that D1 and D2 receptor mRNAs were differentially expressed during development. Two dopamine receptor mRNAs were expressed mainly in the retina, and rarely detected in ciliary body and choroid in adult monkey eyes. During development, a large amount of D2 receptor mRNAs was detected at ED 60 and the level increased slowly throughout the gestation period. However, D1 receptor mRNAs was detected at low level by ED 70, and increased steeply at ED 140. D1 and D2 receptor mRNAs both reached maximum level at ED 140 and slightly decreased in the adult. Dopamine receptor mRNAs were localized using in situ hybridization. D1 and D2 receptor mRNAs were both detected in the proximal half of the outer neuroblastic layer at ED 60, extended into the entire region of inner and outer nuclear layers at following stages. it is supposed that dopamine receptor subtypes play different roles on retinal development because D1 and D2 dopamine receptor subtype mRNAs were expressed differentially according to developing stages in fetal monkey retina.
Keywords: opamine receptor, development, monkey retina, mRNA expression