scholarly journals Colocalization of immunoreactivity for neurokinin 1, NMDA and AMPA receptors in rat nucleus tractus solitarii

2006 ◽  
Vol 20 (4) ◽  
Author(s):  
Li‐Hsien Lin ◽  
William T. Talman
Keyword(s):  
Ampa Receptors ◽  
Nucleus Tractus Solitarii ◽  
Neurokinin 1

scholarly journals Silent Synapses in Developing Rat Nucleus Tractus Solitarii Have AMPA Receptors

2008 ◽  
Vol 28 (18) ◽  
pp. 4624-4634 ◽  
Author(s):  
B. Balland ◽  
P. Lachamp ◽  
J.-P. Kessler ◽  
F. Tell
Keyword(s):  
Ampa Receptors ◽  
Nucleus Tractus Solitarii ◽  
Silent Synapses ◽  
Developing Rat

scholarly journals Astrocytic modulation of glutamatergic synaptic transmission is reduced in NTS of rats submitted to short-term sustained hypoxia

2019 ◽  
Vol 121 (5) ◽  
pp. 1822-1830 ◽  
Author(s):  
Daniela Accorsi-Mendonça ◽  
Leni G. H. Bonagamba ◽  
Benedito H. Machado
Keyword(s):  
Synaptic Transmission ◽  
Ampa Receptors ◽  
Nucleus Tractus Solitarii ◽  
Resting Membrane Potential ◽  
Density Control ◽  
Glutamatergic Synaptic Transmission ◽  
Nmda Current ◽  
New Findings ◽  
Sustained Hypoxia ◽  
Respiratory Responses

Sustained hypoxia (SH) activates chemoreceptors to produce cardiovascular and respiratory responses to bring the arterial partial pressure of O2 back to the physiological range. We evaluated the effect of SH (fraction of inspired O2 = 0.10, 24 h) on glutamatergic synaptic transmission and the interaction neuron-astrocyte in neurons of the nucleus tractus solitarii (NTS). Tractus solitarius (TS) fiber stimulation induced glutamatergic currents in neurons and astrocytes. SH increased α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid/kainate (AMPA/kainate) [−183 ± 122 pA ( n = 10) vs. −353 ± 101 pA ( n = 10)] and N-methyl-d-aspartate (NMDA) current amplitude [61 ± 10 pA ( n = 7) vs. 102 ± 37 pA ( n = 10)]. To investigate the effects of SH, we used fluoroacetate (FAC), an astrocytic inhibitor, which revealed an excitatory modulation on AMPA/kainate current and an inhibitory modulation of NMDA current in control rats. SH blunted the astrocytic modulation of AMPA [artificial cerebrospinal fluid (aCSF): −353 ± 101 pA vs. aCSF + FAC: −369 ± 76 pA ( n = 10)] and NMDA currents [aCSF: 102 ± 37 pA vs. aCSF + FAC: 108 ± 32 pA ( n = 10)]. SH increased AMPA current density [control: −6 ± 3.5 pA/pF ( n = 6) vs. SH: −20 ± 12 pA/pF ( n = 7)], suggesting changes in density, conductance, or affinity of AMPA receptors. SH produced no effect on astrocytic resting membrane potential, input resistance, and AMPA/kainate current. We conclude that SH decreased the neuron-astrocyte interaction at the NTS level, facilitating the glutamatergic transmission, which may contribute to the enhancement of cardiovascular and respiratory responses to baro- and chemoreflexes activation in SH rats. NEW & NOTEWORTHY Using an electrophysiological approach, we have shown that in nucleus tractus solitarii (NTS) from control rats, astrocytes modulate the AMPA and NMDA currents in NTS neurons, changing their excitability. Sustained hypoxia (SH) increased both glutamatergic currents in NTS neurons due to 1) a reduction in the astrocytic modulation and 2) an increase in the density of AMPA receptors. These new findings show the importance of neuron-astrocyte modulation in the excitatory synaptic transmission in NTS of control and SH rats.

scholarly journals Neurochemical changes in rat nucleus tractus solitarii after ablation of neurons with neurokinin‐1 receptors

2009 ◽  
Vol 23 (S1) ◽  
Author(s):  
Li‐Hsien Lin ◽  
Otar M. Taktakishvili ◽  
Deidre N. Dragon ◽  
William T. Talman
Keyword(s):  
Nucleus Tractus Solitarii ◽  
Neurochemical Changes ◽  
Neurokinin 1

scholarly journals Ventilatory effects of substance P-saporin lesions in the nucleus tractus solitarii of chronically hypoxic rats

2011 ◽  
Vol 301 (2) ◽  
pp. R343-R350 ◽  
Author(s):  
Katherine A. Wilkinson ◽  
Zhenxing Fu ◽  
Frank L. Powell
Keyword(s):  
Substance P ◽  
Chronic Hypoxia ◽  
Acute Hypoxia ◽  
Inhibitory Effect ◽  
Nucleus Tractus Solitarii ◽  
Neurokinin 1 Receptor ◽  
Ventilatory Responses ◽  
Ventilatory Drive ◽  
Ventilatory Effects ◽  
Neurokinin 1

During ventilatory acclimatization to hypoxia (VAH), time-dependent increases in ventilation lower Pco2 levels, and this persists on return to normoxia. We hypothesized that plasticity in the caudal nucleus tractus solitarii (NTS) contributes to VAH, as the NTS receives the first synapse from the carotid body chemoreceptor afferents and also contains CO2-sensitive neurons. We lesioned cells in the caudal NTS containing the neurokinin-1 receptor by microinjecting the neurotoxin saporin conjugated to substance P and measured ventilatory responses in awake, unrestrained rats 18 days later. Lesions did not affect hypoxic or hypercapnic ventilatory responses in normoxic control rats, in contrast to published reports for similar lesions in other central chemosensitive areas. Also, lesions did not affect the hypercapnic ventilatory response in chronically hypoxic rats (inspired Po2 = 90 Torr for 7 days). These results suggest functional differences between central chemoreceptor sites. However, lesions significantly increased ventilation in normoxia or acute hypoxia in chronically hypoxic rats. Hence, chronic hypoxia increases an inhibitory effect of neurokinin-1 receptor neurons in the NTS on ventilatory drive, indicating that these neurons contribute to plasticity during chronic hypoxia, although such plasticity does not explain VAH.

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