The current commercial formulation of PBDEs is decaBDE (10 bromines). PBDEs are similar in structure to PCBs but the bromide radical substitutes for chloride ( Covaci et al., 2011 Wiseman et al., 2011). After two accidental contamination incidents that lead to death and several adverse health effects in humans, PCBs were banned from production in 1977 but still linger in human tissues and the environment ( Lang, 1992 Mariussen and Fonnum, 2006 Safe, 1993 Wu et al., 2011). They are lipophilic and bioaccumulate in wildlife and humans ( de Wit, 2002 Kodavanti et al., 1998 Tilson et al., 1998). Industrial organohalogens such as polychlorinated bi-phenyls (PCBs) and polybrominated diphenyl ethers (PBDEs), widely used as flame retardants, are neurotoxic agents and neuroendocrine disruptors that pollute outdoor and indoor environments ( de Wit et al., 2012 Birnbaum and Staskal, 2004). It has been well established that a wide variety of environmental pollutants have specific effects on the neuroendocrine systems of mammals, therefore, the concept of neuroendocrine disruptors was developed ( Leon-Olea et al., 2014 Currás-Collazo, 2011 Waye and Trudeau, 2011). Therefore, the central and peripheral AVP are essential to maintain osmoregulation ( Ludwig and Leng, 1998 Riphagen and Pittman, 1986 Wotjak et al., 1994). Somatodendritic AVP exerts autoinhibitory control over plasma AVP hormonal output. In response to this activation, MNCs produce both AVP and OXT that are released into the systemic circulation from axon terminals located in the neurohypophysis and within the PVN and the SON from soma and dendrites (somatodendritic release) ( Hatton et al., 1978 Ludwig and Leng, 1998 Ludwig et al., 1994). Osmotic and volume stimuli, such as dehydration and hemorrhage, activate magnocellular neuroendocrine cells (MNCs) in the paraventricular (PVN) and supraoptic nuclei (SON) of the hypothalamus. These neuropeptides exert a wide range of actions and control not only upon water and sodium excretion by the kidneys, they also influence cardiovascular responses, learning and memory, thermoregulation, social, sexual, reproductive behavior and stress-related responses, among others ( Cunningham and Sawchenko, 1991 Pittman and Bagdan, 1992 Riphagen and Pittman, 1986 Neumann and Landgraf, 2012 Witt, 1995). The neuropeptides secreted by the hypothalamic-neurohypophysial system, vasopressin (AVP) and oxytocin (OXT), play key roles in homeostasis and fine-tuning of osmotic regulation ( Bourque, 2008 Schrier and Martin, 1998 Weitzman and Kleeman, 1979). The maintenance of water homeostasis is vital for living beings. Therefore, A1254 may interfere with the activation of AVP mRNA transcript levels and protein, causing a central dysfunction of vasopressinergic system.

cFOS mRNA expression increased in A1254 dehydrated groups, suggesting that the AVP-IR decrease was not due to a lack of the response to the osmotic activation. In contrast, the exposed groups did not show this response to osmotic activation, they showed significant reduction in AVP-IR neurons, and AVP mRNA expression as compared to the hyperosmotic controls. The results confirmed a physiological increase in AVP-immunoreactivity (AVP-IR) and gene expression in response to osmotic challenge as reported elsewhere. Animal groups were: vehicle (control) exposed to either A1254 or DE-71 both, control and exposed, subjected to osmotic challenge. cFOS mRNA expression was evaluated in order to determine neuroendocrine cells activation due to osmotic stimulation. The aim of this research was to evaluate the effects of perinatal exposure to A1254 or DE-71 (30 mg kg/day) on AVP transcription and protein content in the paraventricular and supraoptic hypothalamic nuclei, of male and female rats, by in situ hybridization and immunohistochemistry. Our group reported that rats perinatally exposed to Aroclor-1254 (A1254) and DE-71 (commercial mixtures of PCBs and PBDEs) decrease somatodendritic vasopressin (AVP) release while increasing plasma AVP responses to osmotic activation, potentially emptying AVP reserves required for body-water balance.

They affect the vasopressinergic system but their disruptive mechanisms are not well understood. Polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) are environmental pollutants that produce neurotoxicity and neuroendocrine disruption.

Fidelia juarez