An experimental study of the pathogenesis of the selective lesion of the globus pallidus in acute carbon monoxide poisoning in cats. With special reference to the chronologic change in the cerebral local blood flow.

Twenty-eight mature cats were exposed to 0.3% carbon monoxide (CO) gas for 90-193 min using artificial ventilation. The systemic blood pressure (BP), venous pressure (VP), blood flow of the left common carotid artery (CF), and blood gas were monitored. The local blood flow (LBF) of the globus pallidus, putamen, or claustrum was measured by the hydrogen clearance method. Pallidal lesions were found histologically in 14 cats. The period of CO inhalation and the time thereafter were divided into the following four stages in the animals with pallidal lesions. Stage 1: Initial phase with rapid increase in the CF and LBF, and rapid decrease in the BP. Stage 2: Middle phase with slow decrease in the BP, CF, and LBF. Stage 3: Terminal phase with rapid decrease in the BP, CF, and LBF. Stage 4: Recovery phase. The changes in stage 3 were not so prominent in the animals without pallidal lesions. The LBF of the globus pallidus of the animals with lesions decreased to 67.3 +/- 20.7% of the initial value at the terminal stage of CO inhalation, while it was 188 +/- 46.7% in those without lesions. The difference was statistically significant (P less than 0.01). The LBF of the putamen or claustrum in the animals with lesions in the globus pallidus was 140 +/- 24.6% at this stage, and it was significantly higher than that of the globus pallidus (P less than 0.01). Other factors, such as CO inhalation time, degree of acidosis, and terminal CO-Hb concentration, did not correlate with the occurrence of the pallidal lesion.