Ischemia-Reperfusion Injury

Question 1

What rxn is the main source of energy in the Brain?

Answer 1

Carbohydrate Oxidation

Question 2

NR2B

Answer 2

• Can be injected intravenously after a Stroke
• Protected against Brain Damage
• Improved Neurological fxns

Question 3

Where are metabolic rates higher in the brain? White or Gray Matter?

Answer 3

Gray Matter

• Cell nucleus

Question 4

Brain energy use breakdown

Answer 4

• 75% for SIGNALING

- 25% for maintain essential CELLULAR ACTIVITY

Question 5

Risk of Thrombolytics

Answer 5

• May cause Fatal Edema

Or

• May cause INTRA-cranial Hemorrhage

Question 6

Glycogen on brain energy utilization

Answer 6

Actively utilized by NERVE Cells

• 2% of total metabolic rate compared to Glucose

Question 7

Ketone Bodies on brain energy utilization

Answer 7

• Used during SUCKLING

- Due to High FAT content in milk

Question 8

Characteristics of the Penumbra

Answer 8

• Area of REDUCED cerebral flow
• Impaired PROTEIN Synthesis
• PRESERVED energy metabolism

Question 9

Pasteur effect

Answer 9

• Fall in PO2 levels leads to enhanced Lactate Production

Question 10

Excitotoxic Injury

Answer 10

• Both NMDA and AMPA/kainate Overactivation
• Loss of Gradients lead to build of EC Glutamate
• INFLUX of Ca++
• Activate toxic pathways

Question 11

The brain is only _____% body weight, but uses ______ of the energy consumed.

Answer 11

• 2%

- 20%

Question 12

Types of Ischemia

Answer 12

1. FOCAL Cerebral Ischemia

2. GLOBAL Cerebral Ischemia

Question 13

Ischemic Core

Answer 13

• Known as the UMBRA

- Injury grows over TIME

Question 14

What accounts for the Majority of Strokes?

Answer 14

Focal Ischemia

Question 15

What does PET imaging rely on?

Answer 15

• On Quantitative IC trapping of DG-6-PHOSPHATE

- Enables assays of HEXOKINASE Rxn in ALL regions of the brain in Conscious individuals

Question 16

Thrombolytics

Answer 16

• THROMBOLYSIS or EMOLECTOMY
• Infusion of TPA intravenously
• Reperfusion reestablishes CIRCULATION

Question 17

Penumbra

Answer 17

• The Rim or area surrounding the CORE

Question 18

Penumbra Protection

Answer 18

• DHA (O3FA)
• Found in Cold water fish
• POTENT anti inflammatory activity

Question 19

Glucose on brain energy utilization

Answer 19

• Essential for the brain

- Most important energy source

Question 20

Window of opportunity for Focal Ischemia

Answer 20

• Short

- If adequate blood supply not established w/in 3 hours, NECROSIS extends to the Penumbra

Question 21

Lactate on brain energy utilization

Answer 21

Important during Post NATAL period

Question 22

PET Imaging

Answer 22

Position Emission Tomography

• Uses 2-deoxy-glucose in animals
• Uses 2-fluoro-deoxy-glucose in HUMANS

Question 23

Stroke Outcome depends on what?

Answer 23

• The part of the brain affect

- Which type of cells affected

Question 24

What does the Astrocyte release? Where?

Answer 24

• Lactate

- To BOTH the Post-Synaptic Neuron and the Target Neuron

Question 25

Neuroprotective Strategies for dealing with Stroke.

Answer 25

- GABA Agonist - OMEGA 3 FA (DHA) - Heat Shock Responses

Question 26

MRS stands for what?

Answer 26

Magnetic Resonance Spectroscopy

Question 27

FOCAL Cerebral Ischemia

Answer 27

- Focal disruption of blood flow to a part of the brain | - Due to OCCLUSION of an Artery

Question 28

Ischemic Episode

Answer 28

- Cells move from AEROBIC metabolism to GLYCOLYSIS - EFFLUX of K+ - Na+ and Ca++ gradients collapse - INFLUX of CA++ into the cell - Release of NT

Question 29

Regulation of Cerebral Metabolism

Answer 29

- CONTINUOUS Cerebral function is required to sustain brain function - Oxygen Concentration in cerebral Venous blood is LOWER that Cerebral arterial blood

Question 30

NPD1

Answer 30

- DHA derivative - Acts Against APOPTOSIS - Promotes Cell serval - Inhibits Brain Ischemia

Question 31

Energy consumption b/w Excitatory and Inhibitory neurons

Answer 31

Both use EQUIVALENT amounts of energy

Question 32

GLOBAL Cerebral Ischemia

Answer 32

- TRANSIENT impairment of blood flow to the WHOLE brain - Happens during Cardiac Arrest - Neurons more sensitive than Glial cells - SELECTIVE loss of Vulnerable Neuronal populations

Question 33

How many ppl suffer from a stroke annually? How many of those Die?

Answer 33

- 15 million - 6 million * Second leading cause of Death and Disability worldwide*

Question 34

MRS Utilization

Answer 34

- Utilizes Glucose labeled w/ RADIOACTIVE Isotopes (3H, 14C, 11C) Or - STABLE Isotope (13C)

Question 35

What does the brain mainly use for energy utilization?

Answer 35

- Glucose - Glycogen - Lactate (Monocarboxylic acids) - Ketone bodies

Question 36

Extraction of O2 vs Glucose by brain cells

Answer 36

O2 - High extraction for O2 - 50% - 70% Glucose - 10%

Question 37

Fxn of MRS

Answer 37

- Allows assessment of Glucose metabolites - NMR spectra obtained (Unique) - Used to determine metabolism of precursors via specific Neuronal and Glial pathways

Question 38

T/F: The brain is Expensive/Inefficient in terms of Energy Usage

Answer 38

True