The Increase in Signaling by Kisspeptin Neurons in the Preoptic Area and Associated Changes in Clock Gene Expression That Trigger the LH Surge in Female Rats Are Dependent on the Facilitatory Action of a Noradrenaline Input

Author(s):Show less -

Kalil, Bruna ^[1] ; Ribeiro, Aline B. ^[1] ; Leite, Cristiane M. ^[2] ; Uchoa, Ernane T. ^{[1, 3]} ; Carolino, Ruither O. ^[2] ; Cardoso, Thais S. R. ^[4] ; Elias, Lucila L. K. ^[1] ; Rodrigues, Jose A. ^[1] ; Plant, Tony M. ^[5] ; Poletini, Maristela O. ^[4] ; Anselmo-Franci, Janete A. ^[2]

Affiliation

^[1] Univ Sao Paulo, Fac Med Ribeirao Preto, Dept Fisiol, BR-14049900 Sao Paulo - Brazil

^[2] Univ Sao Paulo, Fac Odontol Ribeirao Preto, Dept Morfol Fisiol & Patol Basica, BR-14049900 Sao Paulo - Brazil

^[3] Univ Estadual Londrina, Dept Ciencias Fisiol, BR-86051990 Londrina, PR - Brazil

^[4] Univ Fed Minas Gerais, Inst Ciencias Biol, Dept Fisiol & Biofis, BR-31270901 Belo Horizonte, MG - Brazil

^[5] Univ Pittsburgh, Sch Med, Dept Obstet Gynecol & Reprod Sci, Pittsburgh, PA 15213 - USA

• Document type: Journal article
• Source: Endocrinology; v. 157, n. 1, p. 323-335, JAN 2016.
• Web of Science Citations: 2

Abstract

In rodents, kisspeptin neurons in the rostral periventricular area of the third ventricle (RP3V) of the preoptic area are considered to provide a major stimulatory input to the GnRH neuronal network that is responsible for triggering the preovulatory LH surge. Noradrenaline (NA) is one of the main modulators of GnRH release, and NA fibers are found in close apposition to kisspeptin neurons in the RP3V. Our objective was to interrogate the role of NA signaling in the kisspeptin control of GnRH secretion during the estradiol induced LH surge in ovariectomized rats, using prazosin, an alpha 1-adrenergic receptor antagonist. In control rats, the estradiol-induced LH surge at 17 hours was associated with a significant increase in GnRH and kisspeptin content in the median eminence with the increase in kisspeptin preceding that of GnRH and LH. Prazosin, administered 5 and 3 hours prior to the predicted time of the LH surge truncated the LH surge and abolished the rise in GnRH and kisspeptin in the median eminence. In the preoptic area, prazosin blocked the increases in Kiss1 gene expression and kisspeptin content in association with a disruption in the expression of the clock genes, Per1 and Bmal1. Together these findings demonstrate for the first time that NA modulates kisspeptin synthesis in the RP3V through the activation of alpha 1-adrenergic receptors prior to the initiation of the LH surge and indicate a potential role of alpha 1-adrenergic signaling in the circadian-controlled pathway timing of the preovulatory LH surge. (AU)

• FAPESP's process: 10/12642-9 - "Noradrenergic modulation of kisspeptin/GnRH systems and clock genes expression in the control of the estradiol induced LH surge in ovariectomized rats"
• Grantee: Bruna Kalil Cutti
• Support Opportunities: Scholarships in Brazil - Doctorate