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Control of sympathetic and phrenic nerve activity by cholinergic mechanisms in the nucleus of the solitary tract (NTS)
Author(s) -
Furuya Werner Issao,
Bassi Mirian,
Menani José Vanderlei,
Colombari Eduardo,
Zoccal Daniel Breseghello,
Almeida Colombari Débora Simões
Publication year - 2012
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.26.1_supplement.702.11
Subject(s) - muscarinic acetylcholine receptor , acetylcholine , cholinergic , chemistry , atropine , phrenic nerve , parasympathetic nervous system , endocrinology , saline , medicine , solitary nucleus , respiratory system , receptor , autonomic nervous system , heart rate , blood pressure
Cholinergic receptors are present in the NTS and acetylcholine (ACH) microinjected into the medial NTS (mNTS) induces hypotension and bradycardia in rats (da Silva et al., 2008; AJP , 295, p R1774). In the present study, we tested the changes in the sympathetic and phrenic nerve activities produced by ACH injected alone or combined with atropine (ATR, muscarinic antagonist) into the mNTS or into the commissural NTS (cNTS). Decorticated arterially‐perfused in situ preparations of male Holtzman rats (60–90 g, n=5–6) were used to record thoracic sympathetic (tSNA) and phrenic nerve (PNA) activities. ACH (10 mM in 60 nL) was injected into the mNTS or cNTS before and 10 min after ATR (17 and 67 mM in 60 nL). Saline was injected as control. ACH into the mNTS reduced the tSNA (−66.1 ± 6.0 % vs. saline: −0.6 ± 3.3 % of baseline) and PNA frequency (−39.7 ± 2.7 % vs. saline: −2.4 ± 2.6 % of baseline), a response attenuated by ATR (67 mM) into the mNTS (tSNA: −29.7 ± 5.2 % and PNA: −12.8 ± 4.6 %, p<0.05). ACH into the cNTS increased PNA frequency (33.1 ± 6.8 %, vs. saline: −6.4 ± 2.7 %), without changing tSNA. ATR (17 mM) into the cNTS reduced the ACH‐induced increase in PNA frequency (8.6 ± 6.4 %, p<0.05). These data suggest that ACH acting on muscarinic receptors in the NTS may play an important role in the control of sympathetic and respiratory activities with distinct responses depending on the NTS level. Supported by: FAPESP, CNPq.