The weaning period promotes alterations in the orexin neuronal population of rats in a suckling-dependent manner

Author(s)

Diniz, Giovanne B. ^[1] ; Candido, Paulo L. ^{[1, 2]} ; Klein, Marianne O. ^[1] ; Alvisi, Renato D. ^[3] ; Presse, Francoise ^{[4, 5]} ; Nahon, Jean-Louis ^{[4, 5, 6]} ; Felicio, Luciano F. ^[3] ; Bittencourt, Jackson C. ^{[1, 7]}

Affiliation

^[1] Univ Sao Paulo, Inst Biomed Sci, Dept Anat, Lab Chem Neuroanat, BR-05508000 Sao Paulo - Brazil

^[2] Santa Marcelina Med Sch, Dept Anat, Sao Paulo - Brazil

^[3] Univ Sao Paulo, Sch Vet Med, Dept Pathol, Sao Paulo - Brazil

^[4] Inst Pharmacol Mol & Cellulaire, CNRS UNS UMR 7275, Valbonne - France

^[5] Univ Cote dAzur, Nice - France

^[6] Stn Primatol UPS846 CNRS, Rousset Sur Arc - France

^[7] Univ Sao Paulo, Inst Psychol, Ctr Neurosci & Behav, Sao Paulo - Brazil

• Document type: Journal article
• Source: Brain Structure & Function; v. 223, n. 8, p. 3739-3755, NOV 2018.
• Web of Science Citations: 1

Abstract

The orexin-immunoreactive neurons are part of an important arousal-promoting hypothalamic population. Several groups have investigated these neurons during the lactation period, when numerous physiological alterations occur in the dam's body to cope with the newly acquired metabolic needs of the litter. Although those studies have probed this population during the early and intermediate stages of lactation, few works have examined its response to weaning, including the cessation of the tactile suckling stimulus as the litter stops nursing. Using double immunohistochemistry for orexin and FOS combined with three-dimensional reconstruction techniques, we investigated orexin-synthesizing neurons and their activation at different times during weaning, in addition to the role played by the suckling stimulus. We report here that weaning promoted a decline in the anterior population of orexin-immunoreactive neurons and decreased the number of double orexin-FOS neurons labeled in the central dorsomedial hypothalamus, in addition to reducing the overall number of FOS-immunoreactive cells in the whole tuberal hypothalamus. Disruption of the suckling stimulus from the pups impaired the decrease in the number of anteriorly located orexin-immunoreactive neurons, attenuated the activation of orexin-synthesizing cells in the dorsomedial hypothalamus and reduced the number of FOS-immunoreactive neurons across the tuberal hypothalamus. When taken together, our data suggest that the weaning period is necessary to restore neurochemical pathways altered during the lactation period and that the suckling stimulus plays a significant role in this process. (AU)

• FAPESP's process: 17/17998-5 - Evaluating chronic administration of melanin concentrating hormone (MCH) effects in lactating Long-Evans rats
• Grantee: Marianne Orlandini Klein
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 16/02224-1 - The existence of neurogenesis during the lactation period
• Grantee: Jackson Cioni Bittencourt
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 16/02748-0 - Study of the anatomical basis for a volume transmission mechanism on the Melanin Concentrating Hormone [MCH] peptidergic system
• Grantee: Giovanne Baroni Diniz
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 10/52068-0 - The putative envolvement of melanin-concentrating hormone in the control of lactation
• Grantee: Jackson Cioni Bittencourt
• Support Opportunities: Research Projects - Thematic Grants