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Rostral ventrolateral medulla regulates pancreatic and gastric blood flow
Author(s) -
Verberne Anthony J.M.,
McInerney Kathleen M
Publication year - 2006
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.20.4.a365-c
Subject(s) - rostral ventrolateral medulla , medicine , endocrinology , stimulation , vasomotor , chemistry , blood pressure , hexamethonium , sympathetic nervous system , heart rate
Premotor neurons controlling pancreatic sympathetic outflow originate from several sources including the rostral ventrolateral medulla (RVLM). This study was designed to test the hypothesis that pancreatic sympathetic vasomotor outflow is driven by RVLM neurons. Halothane‐anesthetized, paralysed, male Sprague‐Dawley rats received electrical stimulation (50 Hz, 25–75 μA, 0.5 ms pulse duration, 10 s) of the RVLM region which had been localised electrophysiologically. Pancreatic conductance (G panc ) gastric conductance (G gas ), arterial blood pressure and heart rate were measured. Administration of phenylephrine (5 μg/kg, i.v.) or sodium nitroprusside (5 μg/kg, i.v.) drugs produced decreases and increases in G panc and G gas , respectively. Carbachol (0.5–2.0 μg/kg, i.v., n=5) also produced increases in G panc and G gas indicating the presence a muscarinic vasodilator mechanism. Stimulation of the RVLM (n=5 rats) produced increases in arterial blood pressure accompanied by marked reductions in G panc and G gas . These were abolished by ganglion blockade (hexamethonium bromide, 20 mg/kg, i.v.). Cardiopulmonary vagal afferent stimulation (phenylbiguanide, 10 μg/kg, i.v., n=5) produced depressor responses and increases in G panc and G gas . These data indicate that the RVLM contributes to regulation of the sympathetic vasomotor outflow to the pancreas and stomach. Presumably, non‐RVLM sympathetic premotor cell groups modulate other pancreatic functions such as glucagon release.