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Responses of nucleus tractus solitarius neurons to vanilloid, purinergic and CCK receptor activation
Author(s) -
Browning Kirsteen N,
Travagli R. Alberto
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.624.3
Subject(s) - purinergic receptor , chemistry , cholecystokinin , capsaicin , solitary nucleus , glutamate receptor , neuroscience , receptor , medicine , endocrinology , biology , biochemistry
Recent reports indicate that cardiovascular sensory inputs to neurons in the nucleus tractus solitarius (NTS) can be distinguished based on their response to vanilloid‐ or to purinergic‐ agonists, active only on C‐ or A‐δ fibers respectively. The NTS subnucleus centralis (cNTS) receives vagal afferent inputs from subdiaphragmatic viscera and is involved in vago‐vagal circuits controlling gastrointestinal (GI) motility. We have shown that CCK‐8s increases glutamate release from vagal afferent fibers onto cNTS neurons. Since CCK‐8s is thought to exert its GI‐related effects via activation of C‐fibers only, we aimed to test whether vanilloid and CCK‐8s sensitive inputs to cNTS neurons were distinguishable from those responsive to purinergic agonists. Spontaneous EPSCs were recorded from cNTS neurons in response to perfusion with capsaicin (CAP), α‐β‐met‐ATP (ATP) and/or CCK‐8s. ATP, CAP or CCK‐8s increased sEPSC frequency in 37, 75 and 43% of cNTS neurons, respectively. Approximately 30% of cNTS neurons were responsive to both CCK‐8s and ATP, to CCK‐8s and CAP, or to ATP and CAP while 32% of the neurons were responsive to all three agonists. Interestingly, all neurons responding to ATP or CCK‐8s were also responsive to CAP. Thus, unlike cardiovascular sensory inputs, C‐ and A‐δ inputs to cNTS neurons do not appear to have selective responses to either ATP or CAP. Supported by DK 55530