PT  - JOURNAL ARTICLE
AU  - D E Frail
AU  - A M Manelli
AU  - D G Witte
AU  - C W Lin
AU  - M E Steffey
AU  - R G Mackenzie
TI  - Cloning and characterization of a truncated dopamine D1 receptor from goldfish retina: stimulation of cyclic AMP production and calcium mobilization.
DP  - 1993 Dec 01
TA  - Molecular Pharmacology
PG  - 1113--1118
VI  - 44
IP  - 6
4099  - http://molpharm.aspetjournals.org/content/44/6/1113.short
4100  - http://molpharm.aspetjournals.org/content/44/6/1113.full
SO  - Mol Pharmacol1993 Dec 01; 44
AB  - Receptors for dopamine are present on horizontal cells of fish retina that are linked to the activation of adenylate cyclase. In the present study, the goldfish (Carassius auratus) gene that encodes these receptors, referred to as gfD1, was isolated and analyzed. A single open reading frame within the gfD1 gene encodes a protein of 363 amino acids that is highly homologous with dopamine D1 receptors from rats and humans. Interestingly, the carboxyl terminus of gfD1 lacks 80 amino acids that are present in the mammalian receptor sequences. RNA analysis using the polymerase chain reaction demonstrated that the gene is expressed in the goldfish retina and is intronless within the coding region. The fact that gfD1 encodes a dopamine D1 receptor was demonstrated through pharmacological analysis of transfected cells. Both the gfD1 receptor and the human D1 receptor expressed in mammalian cells had high affinity for SCH-23390 and other D1-specific ligands. In addition, the gfD1 receptor and the human D1 receptor were able to stimulate the accumulation of cAMP in response to SKF-38393 or dopamine. Interestingly, stimulation of both the gfD1 and human receptors with dopamine also resulted in an increase in intracellular Ca2+. Finally, long term pretreatment of transfected cells with dopamine resulted in the desensitization and down-regulation of both the goldfish and human receptors.