Effect of carbon dioxide on neurovascular coupling during cortical epileptic activity in rats.

Abstract

Aim: The aim of the study is to investigate the effect of CO 2 on neurovascular coupling in response to epileptiform activity after trancallosal electric stimulation in rats. Methods: Adult albino rats (250-350g, n=6) were anaesthetized with isoflurane and epidural silver EEG electrodes were implanted and fixed into the skull over sensorimotor cortices. To measure regional cerebral blood flow (rCBF) during epileptic activity a self-made metal holder for Laser Doppler Flowmeter (LDF) probe was fixed to thinned skull with dental acrylic. To measure arterial blood pressure (BP) and arterial blood gasses a plastic catheter was implanted into the common carotid artery. After postsurgical recovery animals were placed in a recording chamber. After 20 minutes of background recording effect of CO 2 on basal BP an rCBF was tested by inflating a mixture of 10%CO 2 , 20%O 2 and 70%N 2 for 30seconds. To assess changes in neurovascular coupling a rat model for myoclonic seizures was used. Biphasic constant current suprathreshold stimulus (8Hz, 15s) was applied under normal or elevated CO 2 atmosphere. Results: Elevated CO2 led to a significant increase of both regional cerebral blood flow and blood pressure. In addition, inhalation of 10%CO2 during electrical stimulation of senzorimotor cortex (8Hz, 15s) caused...

Aim: The aim of the study is to investigate the effect of CO 2 on neurovascular coupling in response to epileptiform activity after trancallosal electric stimulation in rats. Methods: Adult albino rats (250-350g, n=6) were anaesthetized with isoflurane and epidural silver EEG electrodes were implanted and fixed into the skull over sensorimotor cortices. To measure regional cerebral blood flow (rCBF) during epileptic activity a self-made metal holder for Laser Doppler Flowmeter (LDF) probe was fixed to thinned skull with dental acrylic. To measure arterial blood pressure (BP) and arterial blood gasses a plastic catheter was implanted into the common carotid artery. After postsurgical recovery animals were placed in a recording chamber. After 20 minutes of background recording effect of CO 2 on basal BP an rCBF was tested by inflating a mixture of 10%CO 2 , 20%O 2 and 70%N 2 for 30seconds. To assess changes in neurovascular coupling a rat model for myoclonic seizures was used. Biphasic constant current suprathreshold stimulus (8Hz, 15s) was applied under normal or elevated CO 2 atmosphere. Results: Elevated CO2 led to a significant increase of both regional cerebral blood flow and blood pressure. In addition, inhalation of 10%CO2 during electrical stimulation of senzorimotor cortex (8Hz, 15s) caused...