TY - JOUR
T1 - Glutamatergic enteric neurons
AU - Liu, Min Tsai
AU - Rothstein, Jeffrey D.
AU - Gershon, Michael D.
AU - Kirchgessner, Annette L.
PY - 1997
Y1 - 1997
N2 - We tested the hypothesis that glutamate, the major excitatory neurotransmitter of the CNS, is also an excitatory neurotransmitter in the enteric nervous system (ENS). Glutamate immunoreactivity was found in cholinergic enteric neurons, many of which were identified as sensory by their co-storage of substance P and/or calbindin. Glutamate immunoreactivity was concentrated in terminal varicosities with a majority of small clear synaptic vesicles. The immunoreactivities of both AMPA and NMDA receptor subunits were also detected on neurons in both submucosal and myenteric plexuses. The immunoreactivity of the EAAC1 neuronal glutamate transporter was widespread in both plexuses. Glutamate evoked depolarizing responses in myenteric neurons that had fast and slow components. The fast component was mimicked by AMPA, and the slow component was mimicked by NMDA. The fast component and the response to AMPA mimicked fast EPSPs evoked in 2/AH neurons; moreover, fast EPSPs as well as fast glutamate and AMPA responses were blocked by selective AMPA antagonists and potentiated by the glutamate uptake inhibitor L-(-)-threo-3-hydroxyaspartic acid. These observations demonstrate, for the first time, the presence of glutamatergic neurons and glutamate-mediated neurotransmission in the ENS.
AB - We tested the hypothesis that glutamate, the major excitatory neurotransmitter of the CNS, is also an excitatory neurotransmitter in the enteric nervous system (ENS). Glutamate immunoreactivity was found in cholinergic enteric neurons, many of which were identified as sensory by their co-storage of substance P and/or calbindin. Glutamate immunoreactivity was concentrated in terminal varicosities with a majority of small clear synaptic vesicles. The immunoreactivities of both AMPA and NMDA receptor subunits were also detected on neurons in both submucosal and myenteric plexuses. The immunoreactivity of the EAAC1 neuronal glutamate transporter was widespread in both plexuses. Glutamate evoked depolarizing responses in myenteric neurons that had fast and slow components. The fast component was mimicked by AMPA, and the slow component was mimicked by NMDA. The fast component and the response to AMPA mimicked fast EPSPs evoked in 2/AH neurons; moreover, fast EPSPs as well as fast glutamate and AMPA responses were blocked by selective AMPA antagonists and potentiated by the glutamate uptake inhibitor L-(-)-threo-3-hydroxyaspartic acid. These observations demonstrate, for the first time, the presence of glutamatergic neurons and glutamate-mediated neurotransmission in the ENS.
KW - Depolarization
KW - Electrophysiology
KW - Enteric nervous system
KW - Excitatory amine acids
KW - Glutamate transporters
KW - Sensory neurons
UR - http://www.scopus.com/inward/record.url?scp=0031008634&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0031008634&partnerID=8YFLogxK
U2 - 10.1523/jneurosci.17-12-04764.1997
DO - 10.1523/jneurosci.17-12-04764.1997
M3 - Article
C2 - 9169536
AN - SCOPUS:0031008634
SN - 0270-6474
VL - 17
SP - 4764
EP - 4784
JO - Journal of Neuroscience
JF - Journal of Neuroscience
IS - 12
ER -