TY - JOUR
T1 - Characterization of neurons of the nucleus tractus solitarius pars centralis
AU - Baptista, V.
AU - Zheng, Z. L.
AU - Coleman, F. H.
AU - Rogers, R. C.
AU - Travagli, R. A.
N1 - Funding Information:
This work was supported by NIH grants DK#55530 and DK#56373.
PY - 2005/8/9
Y1 - 2005/8/9
N2 - Esophageal sensory afferent inputs terminate principally in the central subnucleus of the tractus solitarius (cNTS). Neurons of the cNTS comprise two major neurochemical subpopulations. One contains neurons that are nitric oxide synthase (NOS) immunoreactive (-IR) while the other comprises neurons that are tyrosine hydroxylase (TH)-IR. We have shown recently that TH-IR neurons are involved in esophageal-distention induced gastric relaxation. We used whole cell patch clamp techniques in rat brainstem slices combined with immunohistochemical and morphological reconstructions to characterize cNTS neurons. Postrecording reconstruction of cNTS neurons revealed two morphological neuronal subtypes; one group of cells (41 out of 131 neurons, i.e., 31%) had a multipolar soma, while the other group (87 out of 131 neurons, i.e., 66%) had a bipolar soma. Of the 43 cells in which we conducted a neurochemical examination, 15 displayed TH-IR (9 with bipolar morphology, 6 with multipolar morphology) while the remaining 28 neurons did not display TH-IR (18 with bipolar morphology, 10 with multipolar morphology). Even though the range of electrophysiological properties varied significantly, morphological or neurochemical distinctions did not reveal characteristics peculiar to the subgroups. Spontaneous excitatory postsynaptic currents (sEPSC) recorded in cNTS neurons had a frequency of 1.5 ± 0.15 events s-1 and an amplitude of 27 ± 1.2 pA (Vh = -50 mV) and were abolished by pretreatment with 30 μM AP-5 and 10 μM CNQX, indicating the involvement of both NMDA and non-NMDA receptors. Some cNTS neurons also received a GABAergic input that was abolished by perfusion with 30-50 μM bicuculline. In conclusion, our data show that despite the heterogeneity of morphological and neurochemical membrane properties, the electrophysiological characteristics of cNTS neurons are not a distinguishing feature.
AB - Esophageal sensory afferent inputs terminate principally in the central subnucleus of the tractus solitarius (cNTS). Neurons of the cNTS comprise two major neurochemical subpopulations. One contains neurons that are nitric oxide synthase (NOS) immunoreactive (-IR) while the other comprises neurons that are tyrosine hydroxylase (TH)-IR. We have shown recently that TH-IR neurons are involved in esophageal-distention induced gastric relaxation. We used whole cell patch clamp techniques in rat brainstem slices combined with immunohistochemical and morphological reconstructions to characterize cNTS neurons. Postrecording reconstruction of cNTS neurons revealed two morphological neuronal subtypes; one group of cells (41 out of 131 neurons, i.e., 31%) had a multipolar soma, while the other group (87 out of 131 neurons, i.e., 66%) had a bipolar soma. Of the 43 cells in which we conducted a neurochemical examination, 15 displayed TH-IR (9 with bipolar morphology, 6 with multipolar morphology) while the remaining 28 neurons did not display TH-IR (18 with bipolar morphology, 10 with multipolar morphology). Even though the range of electrophysiological properties varied significantly, morphological or neurochemical distinctions did not reveal characteristics peculiar to the subgroups. Spontaneous excitatory postsynaptic currents (sEPSC) recorded in cNTS neurons had a frequency of 1.5 ± 0.15 events s-1 and an amplitude of 27 ± 1.2 pA (Vh = -50 mV) and were abolished by pretreatment with 30 μM AP-5 and 10 μM CNQX, indicating the involvement of both NMDA and non-NMDA receptors. Some cNTS neurons also received a GABAergic input that was abolished by perfusion with 30-50 μM bicuculline. In conclusion, our data show that despite the heterogeneity of morphological and neurochemical membrane properties, the electrophysiological characteristics of cNTS neurons are not a distinguishing feature.
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U2 - 10.1016/j.brainres.2005.05.073
DO - 10.1016/j.brainres.2005.05.073
M3 - Article
C2 - 16005442
AN - SCOPUS:23644440806
SN - 0006-8993
VL - 1052
SP - 139
EP - 146
JO - Brain research
JF - Brain research
IS - 2
ER -