Ontogeny of retrograde labeled chemoafferent neurons in the newborn rat nodose-petrosal ganglion complex: An ex vivo preparation

Effect of development on [Ca2+]i transients to ATP in petrosal ganglion neurons: a pharmacological approach using optical recording

“…In this study, using a novel ex vivo preparation of the petrosal ganglion in which chemoreceptor neurons are retrogradely labeled with the calcium sensitive tracer CGDA, we investigated the differences between younger (P5-8) and older (P17-25) animals in 1) [Ca 2ϩ ] i -response patterns to different concentrations of ATP during pharmacological blockade of P2XRs, and 2) differences in P2XR-isoform protein levels in This study is the first to optically record [Ca 2ϩ ] i responses to ATP in a population of chemoafferent cell bodies in the PG. Previously we demonstrated that PG neurons similarly retrogradely labeled with rhodamine dextran-amine (RDA) express tyrosine hydroxylase and have a localization consistent with chemoafferent neurons (31), indicating that the retrograde labeling primarily targets chemoreceptor afferent neurons. Our optical recording approach uniquely allows the simultaneous evaluation of responses in multiple chemoafferent neurons at single-cell resolution.…”

“…The CB/NPG complex was then placed in ice-cold 60% O 2-5% CO2 equilibrated Ringer's solution containing (in mM) 125 NaCl, 5 KCl, 1 NaH2PO4, 1 MgCl2, 11 glucose, 26 NaHCO3, 2 CaCl2, pH 7.4. Retrograde labeling of chemoreceptor afferent neurons with calcium green-1 dextran-amine (CGDA, 3 kDa, Molecular Probes, Eugene, OR) from the CB was performed in preparations from young (n ϭ 4) and older (n ϭ8) groups of animals, as previously described with minor modifications (9,31). In brief, CGDA was dissolved to saturation in PBS (1 l of 1 M, Quality Biological) containing brain-derived neurotrophic factor (BNDF, 5 ng/ml, Sigma) and glial cell-derived neurotrophic factor (GDNF, 5 ng/ml, Sigma).…”

Non-sulfated cholecystokinin-8 reduces meal size and prolongs the intermeal interval in male Sprague Dawley rats

“…However, there are fundamental differences between their study and the current one. First, the previous study utilized young rats weighing 160-180 g while we used adult rats weighing 350-450 g. It is known that the neuronal circuits of the gastrointestinal tract, namely the enteric nervous system (ENS) (Schafer et al, 1999;Faussone-Pellegrini et al, 1996;Belai et al, 1995), and the vagus nerve (Tolosa et al, 2005;Powley et al, 2001;Kuehl-Kovarik & Jacobson, 1996;MacLean, 1985;Kerr, 1975), as well the central ones (Gutkind et al, 1988), continue to develop in young animals. These circuits participate in carrying the peripheral satiety signals e.g.…”

Prenatal development of respiratory chemoreceptors in endothermic vertebrates

“…Postnatal changes occur during the first few weeks after birth, which produce a significant increase in carotid body hypoxic responsiveness to adult-like levels (reviewed by Gauda et al, 2009). Post-natal maturation includes increases in: hypoxic inhibition of background leakage K currents in glomus cells (Wasicko et al, 1999), the proportion of glomus cell K + current that is inhibited by hypoxia (Hatton et al, 1997), the glomus cell intracellular calcium responses to hypoxia (Wasicko et al, 1999), the hypoxia-induced secretion of catecholamines from glomus cells (Donnelly, 2005), the magnitude and dynamic sensitivity of carotid sinus afferent discharge to hypoxia (Kholwadwala et al , 1992), and the innervation density of the glomus cells by nodose-petrosal ganglion nerve fibers (Donnelly, 2005; Tolosa et al, 2005). …”