Brainstem catecholaminergic neurones and breathing control during postnatal development in male and female rats

Abstract

The respiratory network undergoes significant development during the postnatal phase, including the maturation of the catecholaminergic (CA) system. However, postnatal development of this network and its effect on the control of pulmonary ventilation ( ) is not fully understood. We investigated the involvement of brainstem CA neurones in respiratory control during postnatal development [postnatal day (P)7-8, P14-15 and P20-21], in male and female rats, through chemical injury with conjugated saporin anti-dopamine β-hydroxylase (DβH-SAP). Thus, DβH-SAP (420 ng μL ), saporin (SAP) or phosphate buffered solution (PBS) was injected into the fourth ventricle of neonatal Wistar rats of both sexes. and oxygen consumption were recorded 1 week after the injections in unanaesthetized neonatal and juvenile rats during room air and hypercapnia. The resting ventilation was higher in both male and female P7-8 lesioned rats by 33%, with a decrease in respiratory variability being observed in males. The hypercapnic ventilatory response (HCVR) was altered in male and female lesioned rats at all postnatal ages. At P7-8, the HCVR for males and females was increased by 37% and 30%, respectively. For both sexes at P14-15 rats, the increase in during hypercapnia was 37% higher for lesioned rats. A sex-specific difference in HCRV was observed at P20-21, with lesioned males showing a 33% decrease, and lesioned females showing an increase of 33%. We conclude that brainstem CA neurones exert a tonic inhibitory effect on in the early postnatal days of the life of a rat, increase variability in P7-8 males and modulate HCRV during the postnatal phase.

Postnatal intermittent hypoxia enhances phrenic and reduces vagal upper airway motor activities in rats by epigenetic mechanisms

“…A caveat of this method is that it does not consider body temperature for the estimation of tidal volume – a factor that has an effect on this parameter when the plethysmographic chamber is completely sealed (Drorbaugh & Fenn, ). Therefore, although the values of tidal volume of our vehicle‐treated control group were similar to other studies that used conventional whole‐body plethysmography (Patrone, Biancardi, Marques, Bicego, & Gargaglioni, ), we cannot exclude the possibility that the elevated tidal volume of pCIH rats relates to modifications in body temperature – a parameter that we did not evaluate in this study and that requires future experimental verification. However, we observed that the elevated tidal volume of pCIH animals was associated with a significant increase in inspiratory peak flow.…”

Locus Coeruleus Degeneration Induces Forebrain Vascular Pathology in a Transgenic Rat Model of Alzheimer’s Disease

“…DBH-sap has been previously validated as a NE-specific immunotoxin in intraventricular surgeries [34, 58, 59]. DBH IHC revealed a striking loss of fibers within PFC, as well as in adjacent cortical and subcortical regions, in DBH-sap (Fig.…”

Embryonic Thermal Manipulation Affects Ventilation, Metabolism, Thermal Control and Central Dopamine in Newly Hatched and Juvenile Chicks

“…Indeed, the monoaminergic systems play an important role in the control of breathing under resting conditions in most vertebrates (Gargaglioni et al, 2008). Previous studies from our laboratory have demonstrated that catecholaminergic neurons of the brainstem exert an inhibitory tonic effect on neonate rats and an inhibitory modulation under hypoxia and CO 2 exposure in males and females (Patrone et al, 2018(Patrone et al, , 2020. The role of DA in breathing control is related to its actions in both the peripheral chemoreceptors (López-Barneo et al, 2009) and in the brainstem nuclei (Kline et al, 2002).…”