Philip E Coyer

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1. Exposure of 7 L2-L6 neurones to hypoxia for 65 min resulted in hyperpolarization of the membrane potential (EM) from a mean of -49.1 +/- 2.1 to -54.1 +/- 3.6 mV (S.E.). 2. Intracellular potassium ion activities (aiK) increased significantly from 137.7 +/- 4.0 to 155.6 +/- 3.4 mM-K+. This is equivalent to a change in EK from -74.2 mV commensurate with the(More)
Eight cats were subjected to graded hemorrhagic hypotension following bilateral carotid ligation to produce incomplete global cerebral ischemia. Three additional cats served as controls. The somatosensory evoked potential (SEP) and direct cortical response (DCR) were monitored in all animals and in each case, the cortical component of the SEP was abolished(More)
  • P E Coyer
  • Comparative biochemistry and physiology. A…
  • 1986
Membrane potentials (EM), interburst intervals (IBI), burst durations (BD), the numbers of spikes within a burst, and the amplitudes of the burst pacemaker potentials (BPP) were measured in two groups (N = 7 per group) of R15 neurones under conditions of 20, 10 and 5% oxygen and under nitrogen equilibration in suffusates with either Ca2+ (10 mM) or Mg2+ (10(More)
Acute focal ischemia was created in 10 cats by unilateral retro-orbital middle cerebral artery (MCA) occlusion. Regional cerebral blood flow (CBF) was determined utilizing the hydrogen clearance technique from electrode recordings within the gray matter and white matter of the ectosylvian gyrus of both hemispheres. The somatosensory evoked potential (SSEP)(More)
In 24 adult cats, the somatosensory-evoked potential (SEP) and cerebral blood flow (CBF) were measured under paralyzed, anesthetized conditions during exposure to two different ventilatory regimens. Group I cats (ventilated from 20 to 2% oxygen) responded with a significant increase in white matter blood flow from 25.0 +/- 7.8 to 43.8 +/- 10.5 ml/100 g/min(More)
In a focal model of cerebral ischemia (middle cerebral artery (MCA) occlusion in the cat), the existence of a relationship between the latency from the onset of stimulation to the appearance of the cortical component of the somatosensory evoked response and blood flow was explored. White matter blood flow was determined in the left and right hemispheres(More)
The middle cerebral artery was occluded in 18 cats to evaluate the physiological consequences of cerebral blood flow reductions on the somatosensory evoked potential, spontaneous neuronal activity, and oxygen availability in the ipsilateral and contralateral hemispheres. In the ipsilateral ectosylvian gyrus high-grade ischemia was produced as blood flow in(More)
These results may be interpreted as follows: Calcium entry into R15 is brought about by hypoxia. The amount of intracellular calcium is probably buffered by the endoplasmic reticulum and the mitochondria whose processes of oxidative phosphorylation exchange protons for Ca2 + ions. (12, 13, 14) It is known that calcium entry into molluscan neurons(More)
Acute focal ischemia was created in 10 cats by unilateral retro-orbital middle cerebral artery (MCA) occlusion. Regional cerebral blood flow (CBF) was determined utilizing the hydrogen clearance technique from electrode recordings within the gray matter and white matter of the ectosylvian gyrus of both hemispheres. The somatosensory evoked potential (SSEP)(More)