Pyramidal tract responses (PTR) during hypoxia and hypotension.

Abstract

Sundt TM Jr: Clip-grafts for aneurysm and small vessel surgery. Part 4:Relative application to various aneurysms and repair of anterior communicating aneurysms using a right-angle clip holder. SUMMARY In rats with unilateral carotid artery ligation pyramidal tract responses were studied during hypoxia and during trimethaphan-induced hypotension. Observations on EEG activity during hypoxia suggest that unilateral carotid artery ligation produces a more severe perfusion defect in lateral portions of the hemisphere. During hypoxia and during trimethaphan-induced hypotension indirect PTRs disappeared first from the hemisphere on the side of carotid artery ligation and next from the opposite hemisphere. This was followed by loss of direct PTRs in the same order. Animals could not be resuscitated once the direct PTR from the non-ligated hemisphere had disappeared. Hypotension appears to be a late contributing factor in impairing electrocerebral activity during hypoxia in this study.

Systemic Hypoxia and the Depression of Synaptic Transmission in Rat Hippocampus after Carotid Artery Occlusion

“…These results indicate that following unilateral carotid artery occlusion, circulatory and/or metabolic compensation is sufficient to maintain baseline values in both hemispheres, as has been as noted by others (Salford & Siesjo, 1974; Sengupta et al 1974; Sutter & Wiederholt, 1976; Hoffman et al 1983; Busto & Ginsberg, 1985; Payen et al 1996). The lack of effect of a systemically applied adenosine A 1 antagonist on baseline cerebrovascular parameters has also been observed by others (Bryan & Marshall, 1999; Meno et al 2001).…”

“…The interactions of tissue hypoxia and of reduced hippocampal blood flow (HBF) in this ischaemic model with respect to the adenosine‐mediated depression of synaptic transmission are not known. Systemic hypoxia in the rat is associated with a reduction in mean arterial blood pressure (MAP; Sutter & Wiederholt, 1976; Gervitz et al 2001; Wuyam et al 2002). This hypotension, in turn, is associated with reductions in CBF.…”

Effects of Acute Systemic Hypoxia and Hypercapnia on Brain Damage in a Rat Model of Hypoxia-Ischemia

“…A decrease in the MAP, in turn, can be associated with a reduced CBF. Systemic hypoxia is reportedly associated with a reduced MAP in rats[27, 28], and an impaired CBF is believed to be the principal pathological mechanism of hypoxia–ischemia[29]. An increased MAP can lead to an increased CBF, thus alleviating the degree of neurological dysfunction during acute ischemic stroke[30].…”

Mental retardation and neurological deficits in a twin orangutan

“…Nicholson et al[1970] found permanent deficits in visual discrimination and spatial alterations in monkeys that suffered permanent brain damage in response to hypoxia. Sutter and Wiederholt [1976] showed that hypoxia induced permanent damage to the pyramidal motor system. There is evidence from human beings that perinatal hypoxia can be a frequent cause of death in twins.…”