Transcript Electron Energy Loss Spectroscopy

By
Mansur Mulk
MEDBIO 3970Z
 Definition.
 Possible
application.
 Theory.
 Instrumentation.
 CPP
Experiment.
 Experimental Results.
 Conclusion
 Advantages and Limitation.
 Condition Place Preference is an environmental place
conditioning procedure which is a commonly used technique
to model the condition reinforcing effect of drugs in
experimental animals. It is the pairing between a novel
environmental stimulus (place) and a reflex-eliciting stimulus
(drug or in this case PLFMF).
This paradigm is traditionally used to determine if
stimuli are rewarding.
Conditioning a mouse to a novel environment is conducted
by singly or repeatedly placing it in a new environment
while exposing it to a drug or PLFMF.
 If the stimulus is positive the mouse will choose that
environment when given a choice.
 If the stimulus if negative the opposite effect will be
observed.


A lot of information is present in a Condition
Place Preference environment.
 Anti Depression Drug.
 Protective Role of High Blood Pressure on pain
Complaints in the population.(Hagen et. Al., 2005)
 Magnetotherapy, employing static magnetic fields,
millimetre waves and specific pulsed magnetic
fields.(Radzievsky et. al., 2000).

Pain and Nociception:(C. Del Seppia et al. 2007)
“An unpleasant sensory or emotional experience associated with actual or
potential tissue dmage”(Merskey, 1983)


Increase in Pain Sensitivity: in Snails(Kavaliers, 1988)
Increase or Decrease in Pain Sensitivity:
Various combination of dynamic and static fields
(Prato et al., 2000)
 Reduce thermal nociception in:
Snails (Thomas et al., 1997)
Mice (Shupak et al., 2004)
Humans (Shupak et al., 2004)

Influence the vestibular system in:
Humans (Thomas et al., 2001
PLFMF used in this study. The discontinuous 60 Hz field was
identical except for the sinusoidal form in place of the box-like wave
(refractory period identical in both). Yves Bureau, PhD, March 6, 2009
Conditioned place preference
(CPP) apparatus.
CPP apparatus and magnetic field
generator. Helmholtz coils surround
the individual boxes.
1.PLFMF like many narcotics reduce sensation to pain in mice.
2.Narcotics such as morphine easily condition mice to prefer
one environment over another.
3.PLFMF can also successfully be used to condition mice.
Attempted to condition mice to prefer one novel
box over another using morphine and PLFMF.
GROUP MEMBERSHIP
1) Saline injected mice
2) Sham (magnetic field generator is turned on but there is not
power to the coils)
3) 5 mg/kg of morphine sulfate.
4) Complex Neuroelectromagnetic Pulse (Cnp)
5) 60 Hz pulse which is equivalent to the Cnp with respect to
refractory periods in the pulse.
1. Mice were first habituated to a conditioned place preference
apparatus.
2. Following habituation, the amount of time mice spent in either
box or the bridge for a 15 minute session was recorded.
3. For the next 10 days mice were confined for 30 minutes per day
every second day to the box they preferred least while being
exposed to either:
1. Morphine (5 mg/kg)
2. Saline or Sham magnetic field (Control)
3. Cnp
4. 60 Hz
4. On the alternate days mice were exposed to either saline if
drug injected or to a sham magnetic field condition if exposed
to PLFMF while in the preferred box.
5. On the test day the mice were given the choice of spending
time in either the preferred or non-preferred box for 15
minutes.
A mixed analysis of variance was
conducted with pre/post conditioning
and box type as the within subject
variable and treatment as the between
subject variable.
Simple simple main effect analysis was
conducted for condition at the non
preferred box post conditioning.
All results were considered significant
when the probability of making a Type
1 error was less that 5% (p<.05).
All results were interpreted using the
Greenhouse Geisser correction.
1. There was a tendency toward a pre/post conditioning
by box type by treatment interaction, (F(5,74)=1.8,
p=.120) (Figures 1a, 1b). Due to sample size this effect
was not significant.
2. However, a simple simple main effect analysis on treatment
at the non preferred boxes post conditioning was conducted
in spite of this negative result. A significant group
difference was observed (F(3,43)=2.96, p<.05).
3.A post hoc Tukey test did not show any differences
suggesting that the simple simple main effect was due a
combination of treatment groups that differed from the
control group.
4.All-in-all the control group was different from all the
treatment groups combined (Figure 1b).
Time spend after Conditioning
Time Spend Before Conditioning
500
500
Control
60 Hz
Cnp
Morphine
450
Control
60 Hz
Cnp
Morphine
450
400
350
Time (sec)
Time (sec)
400
350
300
300
250
200
250
150
200
0
Pref
Pre
Ntrl P
re
Nonp
re P r
e
Figures 1a: Time spent in either the
preferred, neutal (bridge), or non preferred
box prior to conditioning.
100
0
Pref
Post
Ntrl P
ost
Nonp
re Po
st
Figures 1b: Time spent in either the preferred,
neural (bridge), or non preferred box and after
condition using Morphine, Cnp, 60 Hz, or
Saline.
Box paired with stimulus produced conditioning
effect.
 In order to have an optimistic result sample size
should be 15 individual per group.


Tests animals in a drug-free state.

Sensitive to both reward and aversion.

Allows for simultaneous determination of CPP and neuron activity.

Adaptable to a variety of species;

Utility in probing the neural circuits involved in drug reward.
LIMITATIONS
1.Subject to interpretation based on the notion of novelty seeking.
2.Difficult to interpret when animals prefer one context prior to
drug conditioning.
3.lacks face validity as an experimental protocol of drug reward in
humans.
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