Introduction. Methods. Alphabetical List of Abbreviations. Alphabetical List of Structures. Acknowledgement. References. Gestational Day 12 (GD 12). Gestational Day 14 (GD 14). Gestational Day 16 (GD 16). Gestational Day 18 (GD 18). Each Chapter Includes References. Index.
Abstract: The role of dopaminergic innervation on the postnatal developmental expression of D 1 dopamine receptors was investigated. Bilateral destruction of dopa‐mine‐containing neurons was achieved by treating rats intracisternally with 6‐hydroxydopamine (6‐OHDA) on postnatal day 3, and rats were killed on day 21. To ensure effective reduction of D 1 receptor activation by residual dopamine, a group of 6‐OHDA‐lesioned rats was given twice daily injections of the D 1 receptor antagonist SCH‐23390, from day 4 to 20. D 1 dopamine receptor binding was assessed in the caudate—putamen, nucleus accumbens, and olfactory tubercle by quantitative autoradiographic analysis of [ 3 H]SCH‐23390 binding. In addition, the relative amount of D 1A receptor mRNA was assessed by in situ hybridization of a 35 S‐labeled riboprobe. In the developing rats, neither the amount of [ 3 H]SCH‐23390 binding nor the amount of D 1A receptor mRNA was altered by 6‐OHDA lesioning followed by chronic treatment with SCH‐23390. Thus, bilateral destruction of dopamine‐containing neurons and treatment with SCH‐23390 in neonatal rats did not interfere with the developmental expression of D 1 receptors or alter the levels of mRNA that code for this receptor protein. Treatment of intact rats with SCH‐23390 from postnatal day 4 to 20 also did not alter [ 3 H]SCH‐23390 binding or levels of D 1 receptor mRNA. However, adult rats treated chronically with SCH‐23390 exhibited increased [ 3 H]SCH‐23390 binding but did not show a significant change in D 1 receptor mRNA levels.
