Regional haemodynamic responses to activation of the medial prefrontal cortex depressor region

Citation
Nc. Owens et Ajm. Verberne, Regional haemodynamic responses to activation of the medial prefrontal cortex depressor region, BRAIN RES, 919(2), 2001, pp. 221-231
Citations number
37
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Neurosciences & Behavoir
Journal title
BRAIN RESEARCH
ISSN journal
0006-8993 → ACNP
Volume
919
Issue
2
Year of publication
2001
Pages
221 - 231
Database
ISI
SICI code
0006-8993(20011123)919:2<221:RHRTAO>2.0.ZU;2-F
Abstract
Electrical or chemical stimulation of the medial prefrontal. cortex (MPFC) produces depressor and sympatho inhibitory responses. To characterise the M PFC 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, superio r mesenteric, and iliac arterial vascular conductance using miniaturised Do ppler flow probes. Electrical stimulation of the MPFC (50-100 muA) was used to map the location of the depressor region. Increases in vascular conduct ance (or increases in blood flow) were recorded from the renal (+2.3 +/-0.5 kHz/mmHg x 10(3)), mesenteric (+4.4 +/-0.4 kHz/mmHg x 10(3)), and iliac (8.3 +/-1.0 kHz/mmHg x 10(3)) vascular beds in response to stimulation of th e MPFC depressor region coinciding with the ventral infralimbic (IL) and do rsal 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 synth esis inhibitor N-G-nitro-L-arginine methyl ester (L-NAME, 25 mu mol/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 m esenteric 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 depresso r response is mediated by increased conductance in the hindquarters and mes enteric vascular beds. Furthermore, the depressor response may be mediated, in part, by release of nitric oxide in these vascular beds. (C) 2001 Elsev ier Science B.V. All rights reserved.