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Pyridostigmine enhances vagal influence to the heart but increases renal sympathetic nerve activity in anesthetized rats (1169.14)
Author(s) -
Aguiar Carlos Alberto,
Santos Fernanda,
Salgado Helio,
Fazan Rubens
Publication year - 2014
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.28.1_supplement.1169.14
Subject(s) - pyridostigmine , atropine , heart rate , propranolol , vagus nerve , saline , parasympathetic nervous system , anesthesia , bradycardia , endocrinology , medicine , sympathetic nervous system , cholinergic , chemistry , autonomic nervous system , blood pressure , stimulation , myasthenia gravis
We evaluated effect of acute blockade of plasma acetylcholinesterase with pyridostigmine (PYR) on cardiac sympatho‐vagal balance and on electrical activity of the renal sympathetic nerve (RSN) in anesthetized rats. Cardiac sympathetic and vagal tone were assessed in urethane anesthetized rats by heart rate (HR) responses to propranolol (2 mg/kg, N=14) or methyl‐atropine (1 mg/kg, N=18), respectively, 60 min after treatment with PYR (0.25 mg/kg iv) or saline. Other rats, also under urethane anesthesia, were instrumented for AP and RSN activity recordings. After basal recording the rats received PYR (0.25 mg/kg, iv N=6) or saline (N=4) and the experiment last for 1h. PYR elicited a prompt bradycardia (‐73±6 bpm) that partially recovered, but HR remained lower (387±7 vs 445±9 bpm), 1h after treatment. Sympathetic tone was lower (31±6 vs 69±7 bpm) and vagal tone was higher (86±7 vs 44±5 bpm) in rats treated with PYR. A progressive increase in RSN activity, with no change in BP, was observed after treatment with PYR (40±3, 81±26 and 87±6% at 20, 40 and 60 min after PYR). No change in RSN activity was observed in rats treated with saline. Acute treatment with PYR was effective in enhance parasympathetic and reduce sympathetic tonic influence to the heart. Nevertheless, RSN recording revealed an acute increase in sympathetic nerve traffic elicited by PYR. Grant Funding Source : Supported by FAPESP, CAPES, CNPq.