Dopamine (DA) is a catecholamine neurotransmitter that is distributed in the brain and also in different peripheral organs. In particular, DA receptors (DR) are expressed in luteal cells of various species, but the intrinsic role of the DA/DRs system on corpora lutea (CL) function is still unclear. The main objectives of the present study were to examine in rabbit CL the gene expression of DRs and DA and their immunolocalization, as well as the in vitro effects of DA on the production of progesterone, PGE2, and PGF2a during early, mid, and late luteal stages of pseudopregnancy. Immunoreactivity and gene expression for DR type 1 (D1R) decreased while that for D3R increased in luteal and blood vessel cells from early to late pseudopregnant stages. DA immunopositivity was evidenced only in luteal cells. DA and D1R agonist increased in vitro release of progesterone and prostaglandin E2 (PGE2) by early CL, whereas DA and D3R agonist decreased progesterone and increased PGF2a in vitro release by mid and late CL. These results provide evidence that the DA/DR system exerts a dual modulatory function in controlling the lifespan of CL: the DA/D1R is luteotrophic, while the DA/D3R is luteolytic. The present data shed new light on the physiological mechanisms regulating luteal activity that might improve our ability to optimize reproductive efficiency in mammal species, including humans.
Intrinsic direct role of dopamine in the regulation of rabbit (Oryctolagus cuniculus) corpora lutea: in vitro study
CATONE, Giuseppe;PARILLO, Francesco;VULLO, CECILIA;ZERANI, Massimo;GOBBETTI, Anna;
2014-01-01
Abstract
Dopamine (DA) is a catecholamine neurotransmitter that is distributed in the brain and also in different peripheral organs. In particular, DA receptors (DR) are expressed in luteal cells of various species, but the intrinsic role of the DA/DRs system on corpora lutea (CL) function is still unclear. The main objectives of the present study were to examine in rabbit CL the gene expression of DRs and DA and their immunolocalization, as well as the in vitro effects of DA on the production of progesterone, PGE2, and PGF2a during early, mid, and late luteal stages of pseudopregnancy. Immunoreactivity and gene expression for DR type 1 (D1R) decreased while that for D3R increased in luteal and blood vessel cells from early to late pseudopregnant stages. DA immunopositivity was evidenced only in luteal cells. DA and D1R agonist increased in vitro release of progesterone and prostaglandin E2 (PGE2) by early CL, whereas DA and D3R agonist decreased progesterone and increased PGF2a in vitro release by mid and late CL. These results provide evidence that the DA/DR system exerts a dual modulatory function in controlling the lifespan of CL: the DA/D1R is luteotrophic, while the DA/D3R is luteolytic. The present data shed new light on the physiological mechanisms regulating luteal activity that might improve our ability to optimize reproductive efficiency in mammal species, including humans.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
