[Effect of dopamine on local cortical blood flow and somatosensory evoked potential in acute stage of cerebral ischemia--basic study].

UNLABELLED

Effect of intravenous injection of dopamine on local cortical blood flow (CBF) and somatosensory evoked potential (SEP) was evaluated using canine cerebral ischemia, which was produced by occlusion of unilateral middle cerebral artery. CBF was monitored with H2 clearance method and SEP was recorded by stimulating ischias nerve of contralateral side and P1 to N1 peak to peak amplitude, V1, out of components of SEP was used as a parameter expressing brain function. Systemic arterial pressure was also measured. Protocol in this study is shown in Fig. 1.

RESULTS

1. As to change of systemic arterial pressure during administration of dopamine (Fig. 2) Systolic systemic arterial pressure was significantly increased at doses of dopamine of 25 and 65 gamma compared to the value obtained before initiation of dopamine injection. There was nearly no increase in mean systemic arterial pressure at doses of 5 and 10 gamma and mean systemic arterial pressure increased by 5 to 15 mmHg at doses of 20, 30 and 25 gamma, without significant increase compared to the value before start of dopamine administration. Pulse rate became significantly wider at doses of 10, 20, 30, 25 and 65 gamma. 2) As to increase of local cortical blood flow (CBF) during dopamine injection (Fig. 3, 5) CBF increased at doses of dopamine of 5, 10, 20, 30, 25 and 65 gamma compared to the one before dopamine injection. However, degree of increase of blood flow was not significant. 3) As to recovery of somatosensory evoked potential (SEP) during administration of dopamine (Fig. 4, 6) SEP was recovered at doses of dopamine of 5, 10, 20, 30, 25 and 65 gamma. Degree of recovery of SEP was significant at doses of 5, 20, 30 and 25 gamma.(ABSTRACT TRUNCATED AT 250 WORDS)