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Plasticity of the noradrenergic response in gastric vagal circuits
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.1008.6
Subject(s) - neuroscience , gabaergic , glutamatergic , dorsal motor nucleus , neurotransmission , catecholaminergic , medicine , norepinephrine , yohimbine , endocrinology , chemistry , biology , vagus nerve , stimulation , glutamate receptor , dopamine , receptor , inhibitory postsynaptic potential , antagonist
Catecholaminergic inputs from the nucleus tractus solitarius pars centralis (cNTS) to dorsal motor nucleus of the vagus (DMV) neurons exert profound, vagally mediated effects on gastrointestinal motility. We have shown that opioid and pancreatic polypeptides modulate glutamatergic, but not GABAergic, transmission between NTS and DMV. Elevation of cAMP levels within the brainstem, however, allows transient modulation by these peptides of the otherwise unresponsive GABAergic synapse. The aim of this study was to ascertain whether this short‐term plasticity is a generalized phenomenon also relevant to modulation by catecholamines. Whole cell recordings were made from identified gastric‐projecting rat DMV neurons. Electrical stimulation of the NTS evoked either paired IPSC or EPSC. Norepinephrine and/or the α2 agonist UK 14,304 decreased the amplitude of EPSC; these effects were blocked by yohimbine. The amplitude of the IPSC was, however, unaffected by either agonists unless the levels of cAMP were elevated by pretreatment with agents, such as forskolin, known to increase cAMP levels. These results suggest that, as with opioids and pancreatic polypeptides, the effects of catecholamines on GABAergic transmission depend upon the levels of cAMP within gastric vagal circuits. This short‐term plasticity appears to be a generalized phenomenon within the NTS to DMV GABAergic synapse. Supported by DK 55530