CUTANEOUS MICRODIALYSIS IN THE RAT - INSERTION TRAUMA AND EFFECT OF ANESTHESIA STUDIED BY LASER-DOPPLER PERFUSION IMAGING AND HISTAMINE-RELEASE

Microdialysis makes it feasible to study compounds in the extracellula r space of cutaneous tissue in vivo. The insertion of the microdialysi s probe causes a trauma, which may be anticipated to influence the mic rodialysis process. The effect of anaesthesia on basal skin blood flow and the trauma in the skin after insertion of a microdialysis probe w ere investigated. Hairless rats were anaesthetized either with halotha ne or pentobarbital sodium. Basal skin blood flow and the effect of in sertion of a microdialysis probe were measured by laser Doppler perfus ion imaging. Trauma-induced histamine release was investigated. Rats a naesthetized with pentobarbital sodium showed a stable skin perfusion in contrast to rats anaesthetized with halothane. A significant increa se in blood flow was seen after insertion of the microdialysis probe i n the dermis of rats anaesthetized with pentobarbital sodium, while a change in skin blood flow was not observed in rats anaesthetized with halothane. Probe insertion caused histamine release in rats. A minimum equilibration period of 30 min between probe insertion and the start of the experiment is recommended in future studies, allowing immediate events of the trauma to subside and stabilize.