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We study parmakokinetic of drugs in rats and we use
blood and limph samples. We obtained samples of blood using two
methods: canulation of jugular vein or
retroorbital punction. We woudl like to discuss about it, limitations
of methods, stress of the animals, and
liquid reposition. The retroorbital punction is a good method ?
Thanks.
Maria In=CDs de Toledo
Universidade de S=93o Paulo (post-graduate program)
mitoledo.aaa.yahoo.com
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[Two replies - db]
From: "Chris and Ceil"
To:
Subject: Re: PharmPK sample blood in rats
Date: Sun, 26 Jul 1998 21:31:52 -0000
X-Priority: 3
Why do you use the retro orbital method? I am unfamiliar with it. Would
clipping the tail work just as well?
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X-Sender: catalin.-a-.rousseau.timone.univ-mrs.fr(Unverified)
Mime-Version: 1.0
Date: Mon, 27 Jul 1998 14:20:36 +0200
To: PharmPK.-at-.pharm.cpb.uokhsc.edu
From: Catalin Jacques
Subject: Re: PharmPK sample blood in rats
Dear Dr. Inies de Toledo,
To me, retro-orbital punction should be avoided as it is definitively not
ethical.
It causes huge stress to the animals (thus leading to major changes in
physiological values, especially due to hormonal stress), not to mention the
pain.
Depending on your model (animal awake? freely moving?), it's better to use
canulation of carotida rather than jugular vein since higher arterial
pressure will prevent the line from clotting.
Another very convenient way to collect several blood samples is to quickly
anesthesiate the rat using very short term volatile anesthesy and to
withdraw the desired volume of blood from the jugular vein through the
pectoral muscle with a syringe. The whole takes less than 2 minutes and
doesn't cause much metabolic disturbances, especially if you employ drugs
like isofluran which doesn't interfere much with other compounds or organs
involved in the ADME system.
According to the weight of your rat, you can sample several times a same
animal this way.
Anyway, the critical point is to reduce, if not eliminate, the animal
stress. I attended a couple of years ago a course about effects of stress on
pharmacokinetics and it's simply amazing.
Believe me, take a day off rather than working on a stressed animal!
Good luck with your experiments!
Sincerely,
Pr. Jacques Catalin, Head of Toxicokinetics
***************************************************
Laboratoire de Toxicocin=E9tique et Pharmacocin=E9tique
Facult=E9 de Pharmacie
27, Bd Jean Moulin
13385 Marseille cedex 05
France
Tel: +33 (0)4 91 83 55 09
Fax: +33 (0)4 91 83 56 67
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Dear Dr. Catalin
Thank you for replay my question about retro-orbital punction. When we
need many samples of blood of the same animal during a short time, to
reduce of animal stress is very difficulty in any method.
Thank you.
Maria In=CDs
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Dear Maria,
we are used to obtain multiple sample by cannulation of
the jugular vein. The main problem is the clothing of the tube that
could be avoided by the cannulation of the artery instead of vein. The
artery cannulation is technically more difficult, the blood pressure
induce the loss of large amount of blood and moreover you collect
arteriuos blood... In the use of jugular vein it's preferible washing
the cannula with an heparin solution. Be carefull because the Heparin
could interfer with the PK of the compound!I have never used the
retroorbital sampling, The induced stress should interfer with the
pharmacokinetic of the compound
Dr Cristiana Morandini
Drug Metabolism and Pharmacokinetic Dep.
Glaxowellcome
Verona (Italy)
Tel 045-9218832
Fax: 045-9218153
Email: CM24278.aaa.glaxowellcome.co.uk
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[Two more replies - db]
From: "Bol, Kees [JanBe]"
To: "'PharmPK.-at-.pharm.cpb.uokhsc.edu'"
Subject: RE: PharmPK Re: sample blood in rats
Date: Tue, 11 Aug 1998 14:39:14 +0200
MIME-Version: 1.0
Dear Maria,
we have cannulated the right femoral artery in rats and forwarded the
catheter into the aorta about 0.5 cm from the bifurcation of the common
iliac arteries. The catheters were tunneled sc to exit on the dorsal surface
of the neck. With some practice the surgery can be done without any loss of
blood. In this manner we were able to sample arterial blood frequently
without inducing any stress to the rats. There are situations where arterial
sampling is prefererred. For instance in situations where a fast onset of
effect is observed (eg. anesthesia). Arterial-venous concentration
differences can be quite substantial. Sampling venous blood in these
situations can give the impression of proteresis (or tolerance), because the
effect might peak before the venous concentrations reach their maximum.
Arterial canulation also allows for recording of the arterial pressure wave
to obtain cardiovascular signals, or monitor arterial blood gasses.
The unfriendly retroorbital sampling method should be avoided when frequent
sampling is required.
Kees Bol
Dept. Clinical Pharmacokinetics
Janssen Research Foundation
Beerse, Belgium
PH: 00-32-14-60 61 75
FX: 00-32-14-60 58 34
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Date: Tue, 11 Aug 1998 08:06:27 -0700 (PDT)
From: Maria Toledo
Subject: Re: PharmPK Re: sample blood in rats
To: PharmPK.at.pharm.cpb.uokhsc.edu
MIME-Version: 1.0
Dear Cristiana
Thank you for informations. I can back to use jugular vein and I have
good results.
Maria In=CDs de Toledo
Universidade de S=93o Paulo
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Dear Maria Inies,
If you really need to sample several times a same animal as little as a rat
in a very short period of time, the best way could be to implant a
microdialys probe in the jugular (or femoral) vein.
This method allows continuous sampling without disturbing hemodynamic
values, is compatible with freely moving models, and since the probe can be
implanted a few days before the actual experiment, the animal can recover
from surgery.
The thing is, the use of microdialys method requires some "know-how", it
takes a few weeks (mainly in vitro, on plasma samples spiked with defined
quantities of drug) to study the yield of the membranes and so on.
Moreover, highly lipophilic molecules are likely to stick to the probe, so
this method doesn't necesseraly suit to any kind of drug.
Well, maybe it worths a try?
All the best,
Pr. Jacques Catalin
Laboratoire de Toxicocin=E9tique et Pharmacocin=E9tique
Facult=E9 de Pharmacie
27, Bd Jean Moulin
13385 Marseille cedex 05
Tel: 33 4 91 83 55 09
Fax: 33 4 91 83 56 67
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