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Title: Regional haemodynamic responses to activation of the medial prefrontal cortex depressor region.
Austin Authors: Owens, N C;Verberne, Anthony J M 
Affiliation: Department of Medicine, Clinical Pharmacology and Therapeutics Unit, Austin and Repatriation Medical Centre, University of Melbourne, Heidelberg, Victoria, Australia
Issue Date: 23-Nov-2001
Publication information: Brain Research; 919(2): 221-31
Abstract: Electrical or chemical stimulation of the medial prefrontal cortex (MPFC) produces depressor and sympathoinhibitory responses. To characterise the MPFC depressor response more fully, we determined the regional haemodynamic changes which occurred in response to stimulation of the MPFC. In halothane-anaesthetised rats, we recorded arterial blood pressure and renal, superior mesenteric, and iliac arterial vascular conductance using miniaturised Doppler flow probes. Electrical stimulation of the MPFC (50-100 microA) was used to map the location of the depressor region. Increases in vascular conductance (or increases in blood flow) were recorded from the renal (+2.3+/-0.5 kHz/mmHgx10(3)), mesenteric (+4.4+/-0.4 kHz/mmHgx10(3)), and iliac (+8.3+/-1.0 kHz/mmHgx10(3)) vascular beds in response to stimulation of the MPFC depressor region coinciding with the ventral infralimbic (IL) and dorsal peduncular (DP) cortical areas. Similar responses were obtained after microinjection of the chemical excitant L-glutamate (n=3, 100 nl, 100 mM), indicating that the responses were due to excitation of cell bodies and not due to axons traversing the area. Administration of the nitric oxide synthesis inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME, 25 micromol/kg, i.v., n=5) significantly reduced the MPFC depressor response (51%, 12.5+/-1.2 to 6.1+/-2.5 mmHg). The increases in conductance in the hindquarter and mesenteric vascular beds were significantly reduced after L-NAME treatment (mesenteric by 77%, iliac by 70%), but there was no significant reduction of renal flow (35%). These observations indicate that the depressor region of the MPFC is localised to ventral regions (IL and DP) and that the depressor response is mediated by increased conductance in the hindquarters and mesenteric vascular beds. Furthermore, the depressor response may be mediated, in part, by release of nitric oxide in these vascular beds.
Gov't Doc #: 11701134
Journal: Brain Research
Type: Journal Article
Subjects: Animals
Blood Pressure.drug effects.physiology
Efferent Pathways.drug effects.physiology
Electric Stimulation
Enzyme Inhibitors.pharmacology
Glutamic Acid.metabolism.pharmacology
Iliac Artery.drug effects.physiology
NG-Nitroarginine Methyl Ester.pharmacology
Neural Inhibition.drug effects.physiology
Nitric Oxide.metabolism
Prefrontal Cortex.drug effects.physiology
Rats, Sprague-Dawley
Reflex.drug effects.physiology
Regional Blood Flow.drug effects.physiology
Splanchnic Circulation.drug effects.physiology
Sympathetic Nervous System.drug effects.physiology
Vasodilation.drug effects.physiology
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