Transcript Experimental method and procedure

Effects of different drugs
on isolated intestine
Experimental purpose
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To master the experiment condition of
isolated intestinal smooth muscle and
effects of different drugs on them;
To master the fundamental method of
designing drug interaction and to improve
the designment ability by observing the
relationship between Barium Chloride and
receptors
Gastrointestinal tract
(Smooth muscle)
sympathetic activity
action
receptor
Relaxes
β,α
parasympathetic activity
action
receptor
contracts
M
Experimental animals
• Mice jejunoileum
Experimental drugs
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10-4 mol/L Isoprenaline Hydrochloride
10-4 mol/L Propranolol Hydrochloride
10-3 mol/L Acetylcholine Hydrochloride
10-3 mol/L Atropine Sulfate
10-3 mol/L Verapamil
2% Barium Chloride
Experimental apparatus
• RM6240 signal acquisition and
processing system; Magnus
experimental facility (include Magnus
tube, thermostatic waterbath,
almighty bracket and so on) ;
Tonotransducer; Air pump; Surgical
instruments and syringes, et al.
Experimenta principles
• Intestinal innervation include adrenergic
nerves and cholinergic nerves, and the
latter plays a leading role. Intestinal
receptors include M- cholinergic receptors,
β- adrenergic receptors and a small
quantity of α- adrenergic receptors, whose
stimulation or inhibition can make intestine
contract or relax.
Experimenta principles
• To stimulate M- cholinergic receptors can
induce intestine contraction, and to block
them induce intestine relaxation. On the
contrary, to stimulate β- adrenergic
receptors induce intestine relaxation, and
to block them induce intestine contraction.
All of the above effects ultimately depend
on Ca2+ channel opening or closure.
Sequence of administration
• Action
• Mechanism
• Receptor
first
weak
clear
agonist
second
strong
unclear
antagonist
agonist
Experimental method
and procedure
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Group discussion to design optimal sequence
of administration;
Preparation of experimental facility: Wash
the Magnus tube; Turn on the thermostatic
waterbath and set tempreture at about
37℃; Turn on the computer; Hang the 1g
counterweight and make the baseline rise
about 2 big lattices .
Experimental method
and procedure
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Preparation of intestinal samples:
Fetch a mouse and sacrifice it by
dislocation of cervical vertebra; Open
the abdomen immediately and find the
enterocinetic intestines; Cut the
jejunoileum into 1 to 2cm pieces and put
them in cold Krebs’ solution for future
use.
Experimental method
and procedure
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Fixing samples: Wash your hands and dip
some nutrient fluid on your finger tips;
Fetch a piece of intestinal samples and
tie a thread at each end; Fix the sample,
bung the Magnus tube with rubber
stopper, pour enough nutrient fluid into
the Magnus tube and adjust the length
of the thread to make the baseline rise
about 1 big lattice; Turn on air pump, set
the velocity at 1 to 2 bubbles each
second; Trace a length of normal curve.
Experimental method
and procedure
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The dosage of each drug is 0.1ml,
and another 0.1ml can be added if
the effect is not obvious enough.
Analyze and discuss the
experimental results, finish the
test report.
Attention
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The experiment should be carried
out under the suitable condition and
gas should be supplied continuously;
The manipulation should be light and
soft to keep activity of intestine;
Add the drug over the liquid
surface and never underneath it.
Questions
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Intestinal innervation and their effects;
Intestinal receptor distribution and
different effects by stimulating or
blocking them.
The fundamental principles of designing
sequence of administration.
How can you observe that the
contraction of intestines is based on Ca2+?