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Exaggerated blood pressure and microvascular changes to propofol anaesthesia in SHR in L‐type Ca 2+ channels
Author(s) -
Lawton Bethan K,
Brown Nicola J,
Reilly Charles S,
Brookes Zoe LS
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.a269
Subject(s) - propofol , microcirculation , vasodilation , medicine , anesthesia , blood pressure , venule , vasoconstriction , mean arterial pressure , endocrinology , heart rate
Intravenous anaesthetic (iv) agents act as antagonists of L‐type calcium (Ca 2+ ) channels to elicit changes in peripheral resistance. We propose that L‐type Ca 2+ channel dysfunction during hypertension may contribute to exaggerated decreases in blood pressure and microvascular vasodilation during propofol anaesthesia. Age matched normotensive (Male Wistar Kyoto, WKY) (n=6, 10‐14 weeks old) and spontaneously hypertensive (SHR) rats (n=6) were anaesthetised iv with propofol (6mg/kg, 20‐60mg/kg/hr). Cardiovascular variables were monitored via the carotid artery and ( S ) (−) BAY K8644 (L‐type Ca 2+ channel agonist) administrated via the jugular vein. The mesentery was prepared for intravital microscopy. A dose response to BAY K8644 (0.1, 0.5, 1.0, 5.0, 10.0μg/kg iv, 0.1ml/100g) was performed and mesenteric microvascular (arterioles 13–51μm and venules 20‐76μm) diameters (% change) measured using computerised image analysis (capiscope): preliminary results see fig 1. Arterioles and venules constricted (p<0.05) (arterioles>venules) with BAYK8644 during propofol anaesthesia, accompanied by a greater increase in arterial pressure in SHR than WKY (p<0.05). Arteriolar constriction was also greator in SHR (p<0.05). There may be increased sensitivity of L‐type Ca 2+ channels in the microcirculation of SHR, contributing to exaggerated hypotenson in SHR during propofol anaesthesia. This research is funded by a BJA/RCA project grant. 1.Percentage change in MAP (a) and vessel diameter (b) arterioles and (c) venules