From:
ruth@ferretsabout.co.uk
Date: 2004-01-18 23:42:12 UTC
Subject: RE: Information request
To: ferrethealth@smartgroups.com
Message-ID: <811720.1074481855420.JavaMail.nobody@magnesium.smartgroups.com>
Author wrote:> Now, it DOES work as a neurotoxin, but as a neurotoxin which=
is specifically targeted to insect neurologist which DOES differ from mamm=
al neurology.> I'm going to stop looking but anyone is free to search in Hu=
bmed to know more.The discussion in the UK is over the AURAL use of fiproni=
l for the treatment of ear mites (Otodectes) in ferrets (i.e. the introduct=
ion of Frontline directly into ferrets ears to treat ear mites) and not on =
the use of Frontline spot on/spray by the recommended route (dermally) for =
treatment of those parasites for which it is indicated, e.g. flea, ticks an=
d lices. My understanding from Marc=92s posting was that he would like peop=
le=92s views on the introduction of Frontline/fipronil directly into the ea=
r canal of ferrets as a treatment for ear mites.What I do not understand is=
how it can "work as a neurotoxin, but as a neurotoxin which is specificall=
y targeted to insect neurologist which DOES differ from mammal neurology.=94=
. My understanding is that fipronil acts as an antagonist at the GABA A(Gam=
ma-aminobutyric acid A) receptor. GABAergic neurons are found throughout th=
e mammalian brain i.e. in areas such as the cortex, olfactory bulb, hippoca=
mpus, cerebellum, and retina, and it is well established that there are GAB=
A A receptors in many areas of the mammalian CNS. Furthermore, these mammal=
ian GABA A receptors would appear to be functionally important since picrot=
oxin(which like fipronil, acts as a GABAA antagonist) causes convulsions an=
d death in mammals.Therefore, I would be grateful if someone could tell me =
the mechanism by which fipronil is specifically targeted to insect neurons =
because as yet, despite searching, I have not yet found a clear account of =
the mechanisms by which fipronil is able to interact with insect GABA A rec=
eptors, but not mammalian GABA A receptors.Additionally, if fipronil does n=
ot act on mammalian GABA A receptors, can someone please explain the mechan=
ism by which this substance brings about convulsions and death in rabbits?[=
Moderator's note: there will be at least one vet response with info which =
answers these questions, but they may not be today.] =