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5‐HT 1A ‐receptor (5‐HT 1A R) modulate excitatory and inhibitory neuronal activity within the nucleus tractus solitarii (nTS)
Author(s) -
Ostrowski Tim Daniel,
Kline David D.
Publication year - 2013
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.27.1_supplement.697.15
Subject(s) - excitatory postsynaptic potential , neurotransmission , inhibitory postsynaptic potential , chemistry , solitary nucleus , neuroscience , pharmacology , endocrinology , receptor , biology , biochemistry
Activating central 5‐HT 1A R increases respiration and induces hypotension and bradycardia. The nTS is the first central station for visceral afferent integration and critical for cardiorespiratory responses. Thus, we examined the modulation of synaptic transmission as well as nTS network activity by 5‐HT 1A R in nTS neurons using the patch clamp technique. 5‐HT 1A R were widely distributed within the nTS to cell bodies but not synaptic terminals. Activation of 5‐HT 1A R by 10 μM 8‐OH‐DPAT decreased the amplitude of tractus solitarii‐evoked (TS‐)EPSCs, and decreased overall spontaneous excitatory nTS network activity. These effects persisted in the presence of GABAzine (25 μM) and were antagonized with co‐application of 5‐HT 1A R blocker WAY‐100135 (10 μM). Blockade alone had no effect on TS‐EPSCs but increased excitatory network activity. On the other hand, nTS‐evoked (nTS‐) IPSCs did not change by activation of the 5‐HT 1A R but spontaneous inhibitory nTS network activity decreased. Blocking 5‐HT 1A R increased nTS‐IPSC and inhibitory network activity. Taken together, 5‐HT 1A R are constitutively active within the nTS and their activation decreases afferent transmission as well as overall nTS network activity. These neurophysiological changes may explain the systemic effects seen with exogenous application of 5‐HT 1A R agonists. Support: RO1 HL085108, RO1 HL098602, AHA 12POST11670002.