Glucose metabolism - PowerPoint PPT Presentation

Loading...

PPT – Glucose metabolism PowerPoint presentation | free to download - id: 7ca34-ZDc1Z



Loading


The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
About This Presentation
Title:

Glucose metabolism

Description:

Oxygen consumption follows electrical activity under anaesthesia ... Barbiturate anaesthesia increases glycogen. Specific neurotransmitters activate glycogenolysis ... – PowerPoint PPT presentation

Number of Views:35
Avg rating:3.0/5.0
Slides: 14
Provided by: paulw58
Learn more at: http://fmri.mbi.ufl.edu
Category:

less

Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: Glucose metabolism


1
(No Transcript)
2
Glucose metabolism
  • OGI 6 for aerobic metabolism
  • OGI in resting brain 5.5
  • OGI in active brain is lower
  • CMR cerebral metabolic rate

3
Changes in OGI
  • Fox et al. early PET studies
  • ? CBF ? ?CMRGlc ? 50
  • ? CMRO2 ? 5
  • NMR shows lactate production coincident with BOLD
    activation
  • Glucose oxidation ? 36 ATP
  • Glycolysis ? 2 Lactate 2 ATP
  • Glycogenolysis ? 2 Lactate 1 ATP

4
Questions
  1. Does functional cerebral activity use anaerobic
    glycolysis?
  2. Why is extra lactate produced when oxygen is
    abundant?
  3. What is the role of glycogen?

5
Neurons need energy
  • Glucose oxidation is coupled with glutamate
    release
  • The brain is highly electrically active at rest
  • Oxygen consumption follows electrical activity
    under anaesthesia
  • If the majority of cerebral metabolism is due to
    neuronal activity, why does focal activity use
    less oxygen?

6
Glutamate cycling
ATP
3 Na
7
Glutamate and glucose oxidation
  • Glucose oxidation is nearly equal to glutamate
    cycling
  • 15 non-signaling energetic component
  • All points reflect resting brain activity

8
Resting brain activity
9
Focal activation
10
Glycogen
  • Is glycogen an emergency backup?
  • Barbiturate anaesthesia increases glycogen
  • Specific neurotransmitters activate glycogenolysis

11
(No Transcript)
12
The glycogen shunt
  • Rapid glutamate clearance is essential (10 ms)
  • Glycogen provides a rapid energy source
  • Glycogen is replenished between spikes (costs 1
    ATP)

13
Why the model works
  • Explains why inefficient anaerobic metabolism is
    necessary
  • Accounts for lowered OGI and increased lactate
  • Unit cost of glutamate release remains constant
    (the 34 ATPs in the neuron)
About PowerShow.com