Doppler sonography to monitor flow in different cerebral arteries in the rabbit

Most of the transcranial Doppler (TCD) experimental studies on cerebral hae modynamics have been performed in the rabbit because of the similarity betw een its Willis circle and that of the human, but these studies have mainly bt en limited to the basilar artery. The present study was aimed at extendi ng the use of TCD sonography to all other large cerebral arteries. In anaes thetised rabbits, these arteries were insonated from three different record ing sites, i.e. top-cranial, suboccipital and orbital, using a two-channel pulsed Doppler device equipped with 4 and 8 MHz probes. First, discriminati on between intra- and extracranial arteries was achieved through a standard 'rebreathing' test (hypercapnic-hypoxic stimulation). The distinctive bloo d velocity response patterns, reflecting the different extents of metabolic reactivity in intra- and extracranial territories, are described and discu ssed. Intracranial arteries were then identified on the basis of their resp onse to ipsi- and contralateral common carotid artery occlusion. This proce dure allowed recording from the following arteries: anterior common trunk, anterior cerebral, internal carotid, middle cerebral and basilar; the latte r could be simultaneously monitored with any of the others. This study prov ides an experimental model allowing investigation of regional differences i n the haemodynamic response to neurogenic and pharmacological stimuli.