Neuroendocrine changes in the hypothalamic-neurohypophysial system in the Wistar audiogenic rat (WAR) strain submitted to audiogenic kindling

Author(s)

Valentim-Lima, Evandro ^[1] ; de Oliveira, Jose Antonio Cortes ^[2] ; Antunes-Rodrigues, Jose. ^[2] ; Reis, Luis Carlos ^[3] ; Garcia-Cairasco, Norberto ^[2] ; Mecawi, Andre S. ^[1]

Affiliation

^[1] Univ Fed Sao Paulo, Escola Paulista Med, Dept Biophys, Lab Neuroendocrinol, Sao Paulo - Brazil

^[2] Univ Sao Paulo, FMRP, Dept Physiol, Ribeirao Preto - Brazil

^[3] Univ Fed Rural Rio de Janeiro, Dept Physiol Sci, Seropedica - Brazil

• Document type: Journal article
• Source: Journal of Neuroendocrinology; v. 33, n. 7, SI JUL 2021.
• Web of Science Citations: 0

Abstract

The Wistar audiogenic rat (WAR) strain is used as an animal model of epilepsy, which when submitted to acute acoustic stimulus presents tonic-clonic seizures, mainly dependent on brainstem (mesencephalic) structures. However, when WARs are exposed to chronic acoustic stimuli (audiogenic kindling-AK), they usually present tonic-clonic seizures, followed by limbic seizures, after recruitment of forebrain structures such as the cortex, hippocampus and amygdala. Although some studies have reported that hypothalamic-hypophysis function is also altered in WAR through modulating vasopressin (AVP) and oxytocin (OXT) secretion, the role of these neuropeptides in epilepsy still is controversial. We analyzed the impact of AK and consequent activation of mesencephalic neurocircuits and the recruitment of forebrain limbic (LiR) sites on the hypothalamic-neurohypophysial system and expression of Avpr1a and Oxtr in these structures. At the end of the AK protocol, nine out of 18 WARs presented LiR. Increases in both plasma vasopressin and oxytocin levels were observed in WAR when compared to Wistar rats. These results were correlated with an increase in the expressions of heteronuclear (hn) and messenger (m) RNA for Oxt in the paraventricular nucleus (PVN) in WARs submitted to AK that presented LiR. In the paraventricular nucleus, the hnAvp and mAvp expressions increased in WARs with and without LiR, respectively. There were no significant differences in Avp and Oxt expression in supraoptic nuclei (SON). Also, there was a reduction in the Avpr1a expression in the central nucleus of the amygdala and frontal lobe in the WAR strain. In the inferior colliculus, Avpr1a expression was lower in WARs after AK, especially those without LiR. Our results indicate that both AK and LiR in WARs lead to changes in the hypothalamic-neurohypophysial system and its receptors, providing a new molecular basis to better understaind epilepsy. (AU)

• FAPESP's process: 19/05957-8 - Epilepsies and neuropsyquiatric comorbidities: characterization of the effects of the treatment with cannabidiol and HUF-101 in in vivo and in vitro experimental models
• Grantee: Norberto Garcia Cairasco
• Support Opportunities: Regular Research Grants
• FAPESP's process: 14/50891-1 - INCT 2014: Translational Medicine
• Grantee: Jaime Eduardo Cecilio Hallak
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 14/15218-4 - Energy balance and body fluid homeostasis control: from cells to the physiological systems
• Grantee: Tatiane Vilhena Franco
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 13/09799-1 - Energy balance and body fluid homeostasis control: from cells to the physiological systems
• Grantee: José Antunes Rodrigues
• Support Opportunities: Research Projects - Thematic Grants