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Title: Medial prefrontal depressor response: involvement of the rostral and caudal ventrolateral medulla in the rat.
Austin Authors: Owens, N C;Verberne, Anthony J M 
Affiliation: University of Melbourne, Department of Medicine, Austin and Repatriation Medical Centre, Victoria, Australia
Issue Date: 14-Jan-2000
Publication information: Journal of the Autonomic Nervous System; 78(2-3): 86-93
Abstract: The importance of neurones of the caudal and rostral ventrolateral medulla (CVLM and RVLM, respectively) in mediation of the medial prefrontal cortex depressor response was studied in halothane-anaesthetised rats. Blockade of GABA(A) receptors in the RVLM produced by microinjection of bicuculline (50 nl, 2 mM, n = 6) resulted in reversal of the depressor (-9.5 +/- 1.2 mm Hg) and lumbar sympathetic (-6.5 +/- 5.7 units) responses to pressor (+7.8 +/- 3.5 mm Hg) and sympathoexcitatory (+19.3 +/- 12.5 units) responses and simultaneous blockade of baroreceptor reflex-mediated sympathoinhibition. Baroreflex blockade was reflected by a significant reduction in the gain (slope of the blood pressure vs. lumbar sympathetic nerve discharge regression line) of the reflex. Microinjection of the excitatory amino acid antagonist kynurenic acid (100 nl, 50 mM, n = 6) into the CVLM blocked the baroreflex and significantly reduced the depressor (-9.6 +/- 0.4 to -6.9 +/- 0.6 mm Hg) and lumbar sympathetic (-4.0 +/- 2.1 to 2.9 +/- 1.9 units) responses to medial prefrontal cortex stimulation. These results support the hypothesis that the medial prefrontal cortex depressor response is mediated by a pathway which converges at the level of the RVLM and which is only partly dependent on an excitatory input to caudal ventrolateral medullary neurones.
Gov't Doc #: 10789686
Type: Journal Article
Subjects: Animals
Baroreflex.drug effects.physiology
Blood Pressure.drug effects.physiology
Efferent Pathways.cytology.physiology
Electric Stimulation
Excitatory Amino Acid Antagonists.pharmacology
GABA Antagonists.pharmacology
GABA-A Receptor Antagonists
Kynurenic Acid.pharmacology
Medulla Oblongata.cytology.drug effects.physiology
Prefrontal Cortex.cytology.physiology
Rats, Sprague-Dawley
Receptors, GABA-A.metabolism
Sympathetic Nervous System.cytology.drug effects.physiology
Appears in Collections:Journal articles

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