Anatomy of hypothalamic and diencephalic nuclei involved in seasonal fertility regulation in ewes

Miguel Merchán Jr; Rafael Coveñas; Ignacio Plaza; José Alfonso Abecia; Carlos Palacios

doi:10.3389/fvets.2023.1101024

Anatomy of hypothalamic and diencephalic nuclei involved in seasonal fertility regulation in ewes

Front Vet Sci. 2023 Feb 16:10:1101024. doi: 10.3389/fvets.2023.1101024. eCollection 2023.

Authors

Miguel Merchán Jr^{1

2

3}, Rafael Coveñas^{2

3}, Ignacio Plaza⁴, José Alfonso Abecia⁵, Carlos Palacios¹

Affiliations

¹ Animal Production Area, Department of Construction and Agronomy, Faculty of Agricultural and Environmental Sciences, University of Salamanca, Salamanca, Spain.
² Laboratory of Neuroanatomy of the Peptidergic Systems, Institute for Neuroscience of Castilla y León (INCYL), University of Salamanca, Salamanca, Spain.
³ Recognized Research Group - Molecular Bases of Development (Grupo de Investigación Reconocido - Bases Moleculares del Desarrollo - GIR-BMD), University of Salamanca, Salamanca, Spain.
⁴ Auditory Neuroplasticity Laboratory, Institute for Neuroscience of Castilla y León (INCYL), University of Salamanca, Salamanca, Spain.
⁵ Environmental Science Institute (IUCA), University of Zaragoza, Zaragoza, Spain.

Abstract

In this study, we describe in detail the anatomy of nuclei involved in seasonal fertility regulation (SFR) in ewes. For this purpose, the intergeniculate leaflet of the visual thalamus, the caudal hypothalamic arcuate nucleus, and suprachiasmatic, paraventricular and supraoptic nuclei of the rostral hypothalamus were morphometrically and qualitatively analyzed in Nissl-stained serial sections, in the three anatomical planes. In addition, data were collected on calcium-binding proteins and cell phenotypes after immunostaining alternate serial sections for calretinin, parvalbumin and calbindin. For a complete neuroanatomical study, glial architecture was assessed by immunostaining and analyzing alternate sections for glial fibrillary acidic protein (GFAP) and ionized calcium-binding adapter molecule 1 (IBA1). The results showed a strong microglial and astroglia reaction around the hypothalamic nuclei of interest and around the whole 3^rd ventricle of the ewe brain. Moreover, we correlated cytoarchitectonic coordinates of panoramic serial sections with their macroscopic localization and extension in midline sagittal-sectioned whole brain to provide guidelines for microdissecting nuclei involved in SFR.

Keywords: GFAP; IBA1; Nissl staining; calbindin; calretinin; parvalbumin.

Grants and funding

This study was supported by the Spanish Ministry of Science and Innovation (Ministerio de Ciencia e Innovación – MICINN) Grant number: PID2020-117266RB-C21.