Nucleus tractus solitarii

Increased extracellular concentrations of substance P were measured during hypoxia (9 % O2, at three 5-min intervals in one 30-min period) induced in artificially ventilated cats (Lindefors etal. 1986). 

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In the integration of cardiovascular regulation in the so-called "medullary vasomotor centre" two different areas for pressor and depressor activity are involved. The main part of the depressor area is the nucleus tractus solitarii, which is rich in noradrenaline nerve terminals (DAHLSTROm and FDXE (27)). Ablation of this area leads to hypertension in rats (DOBA and REIS... 

Noradrenaline Brain stem Nucleus tractus solitarii (rat A2A) Barraco et al. 1995... 

Since the orexin receptors are Gq protein-coupled (Alexander et al. 2006), one may assume that this also holds true for the presynaptic orexin receptor(s), but so far no data are available. Nonetheless, the six studies carried out in central nervous preparations permit some conclusions on the post-G protein mechanisms. In all instances, the orexins increased the frequency of spontaneous inhibitory or excitatory postsynaptic potentials or currents. The results differed, however, with respect to the influence of tetrodotoxin. In the medial and lateral hypothalamus (van den Pol et al. 1998 Li et al. 2002), dorsal vagal complex (Davis et al. 2003), and caudal nucleus tractus solitarii (Smith et al. 2002), orexins increased the frequency of the miniature potentials or currents also in the presence of tetrodotoxin, suggesting that they directly influenced the vesicle release machinery (references in italics in Table 5). On the other hand, in the prefrontal cortex (Lambe and Aghajanian 2003) and lat-erodorsal tegmentum (Burlet et al. 2002), the orexins did not retain their facilitatory effect in the presence of tetrodotoxin, suggesting an effect further upstream e.g., on Ca2+ and/or K+ channels. 

Gavras H, Bain GT, Bland L, Vlahakos D, Gavras I. Hypertensive response to saline microinjection in the area of the nucleus tractus solitarii of the rat. Brain Res 1985 343 113-119. 

Saha S, Batten TEC, McWilliam PN (1995b) Glutamate, y-aminobutyric acid and tachykinin-immunoreactive synapses in the cat nucleus tractus solitarii. J Neurocytol 24 55-74. 

Sekizawa S, load JP, Bonham AC (2003) Substance P presynapticaUy depresses the transmission of sensory input to bronchopulmonary neurons in the guinea pig nucleus tractus solitarii. J Physiol 552 547-559... 

Smith CA, Adamson DL, Choudry NB, Fuller RW (1991) The effect of altering airway tone on the sensitivity of the cough reflex in normal volunteers. Eur Respir J 4 1078-1079 Smith BN, Dou P, Barber WD, Dudek FE (1998) VagaUy evoked synaptic currents in the immature rat nucleus tractus solitarii in an intact in vitro preparation. J Physiol 512(Part 1) 149-162 Soya A, Serino R, Fujihara H, Onaka T, Ozaki Y, Saito T, Nakamura J, Ueta Y (2005) Cannabinoids modulate synaptic activity in the rat supraoptic nucleus. J Neuroendocrinol 17 609-615 Spina D, Page CP, Morley J. (1998). Sensory neuropeptides and bronchial hyperresponsiveness.ln Said SI (ed) Prolnflammatory and antunflammatory peptides. Marcel Deckker, New York, pp 89-146... 

Mutolo D, Bongianni F, Fontana GA, Pantaleo T (2007) The role of excitatory amino acids and substance P in the mediation of the cough reflex within the nucleus tractus solitarii of the rabbit. Brain Res BuU 74 284-293... 

Tell F, Jean A (1993) Ionic basis for endogenous rhythmic patterns induced by activation of N-methyl-D-aspartate receptors in neurons of the rat nucleus tractus solitarii. J Neurophysiol... 

Fig. 2 Three types of waveforms of postsynaptic currents recorded from the slice including the nucleus tractus solitarii (NTS) (A). The postsynaptic currents were evoked by stimulation of the solitary tract or the adjacent region. The neurons of the NTS were voltage-clamped at —65-mV holding potential, a excitatory postsynaptic current, b inhibitory postsynaptic current...

Takahama K, Fukushima H, Isohama Y, Kai H, Miyata T (1997b) Inhibition of glycine currents by dextromethorphan in neurones dissociated from the guinea-pig nucleus tractus solitarii. Br J Pharmacol 120 690-694... 

Huang B. H. and Wu J.-Y (1984) Ultrastructural studies on catecholammergic terminals and GABAergic neurons in nucleus tractus solitarii of the medulla oblongata of rat. Brain Res, 302, 57-67... 

Talman, W., Perrone, M. H., Doba, N., and Reis, D. J., 1979, Fulminating hypertension produced by local injection of kainic acid into the nucleus tractus solitarii in the rat,... 

Palkovits, M., and Zaborszky, L., 1977, Neuroanatomy of central cardiovascular control. Nucleus tractus solitarii afferent and efferent neuronal connections in relation to the baroreceptor reflex arc. Prog. Brain Res. 47 9-34. 

Signal transduction pathway(s) linked to the a-amino - 3 - hydroxy - 5-methyl-4-isoxazolepropionate (AMPA)/kainate receptor subtype plays a major role in transmission of sensory information from the airways to the nucleus tractus solitarii and from nucleus tractus solitarii neurones to the airway vagal preganglionic cells, mediating reflexly increased tracheal blood flow, submucosal gland secretion, and airway tone (Haxhiu et al. 2000). 

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