The study was aimed to characterize the inhibitory dopamine (DA) receptor in the pituitary of tilapia. DA D2 and D3 agonists inhibited GnRH-stimulated LH release from tilapia pituitary cells more efficiently than D4 agonists. However, no significant differences were observed between the efficiencies of D2 and D3 drugs. In order to elucidate the signal transduction of the tilapia DA receptor we performed transfection of COS-7 cells with tilapia D2 DA receptor that resulted in the inhibition of forskolin-stimulated cAMP accumulation. Moreover, the tilapia D2 dopamine receptor inhibits adenylate cyclase activity via coupling to pertussis toxin-sensitive G proteins of the Gi/Go family. Our results also show that estradiol up-regulates taDA-R mRNA.
|Number of pages
|Fish Physiology and Biochemistry
|Published - 2003
Bibliographical noteFunding Information:
This research was supported by the Israel Science Foundation No. 775/01.