Objective—To determine concentrations of excitatory
and inhibitory amino acids in CSF of a large number
of dogs with idiopathic epilepsy or genetic epilepsy
and to evaluate changes in CSF amino acid concentration
with regard to drug treatment and sex.
Animals—35 Labrador Retrievers with genetic
epilepsy (20 male and 15 female), 94 non-Labrador
Retrievers with idiopathic epilepsy (71 male and 23
female), and 20 control dogs (10 male and 10 female).
Procedure—Collection of CSF was performed > 72
hours after the occurrence of seizures. Cerebrospinal
fluid concentrations of γ-aminobutyric acid (GABA),
glutamate (GLU), aspartate (ASP), serine, and glycine
were determined by use of high performance liquid
chromatography with electrochemical detection.
Results—CSF concentrations of GABA and GLU
were significantly lower in Labrador Retrievers
with genetic epilepsy (LR-group dogs) than in control-group dogs or in non-Labrador Retrievers with
idiopathic epilepsy (non–LR-group dogs). The GLU-to-GABA ratio was significantly higher in LR-group
dogs than in non–LR-group dogs. CSF concentrations
of GLU and ASP were significantly lower
when all dogs with epilepsy (non–LR- and LR-group
dogs combined) were compared with control-group dogs.
Conclusions and Clinical Relevance—A decrease in
CSF concentrations of GABA appears to play a role in
the pathogenesis of genetically determined epilepsy
in Labrador Retrievers. However, this decrease in CSF
concentrations of GABA may also be a consequence
of seizure activity. The GLU-to-GABA ratio may prove
to be a useful indicator of genetic epilepsy in Labrador
Retrievers. (Am J Vet Res 2004;65:1108–1113)
Objective—To characterize and compare in vitro contractility
patterns of sections of abomasal wall harvested
from cattle of 3 dairy breeds.
Sample Population—Longitudinal and circular
smooth muscle preparations harvested from the
antrum and body of the abomasum of 30 recently
slaughtered Holstein-Friesian, Brown Swiss, and
Simmental X Red Holstein cows.
Procedure—Spontaneous isometric contractions of
specimens in tissue baths of modified Krebs solution
were recorded during a 4-hour period. Maximal amplitude,
frequency of contractions, and change of basal
tension were used to characterize contractility.
Statistical analyses were used to test for differences
among time periods, among breeds, between specimen
locations, and between fiber orientations.
Results—Myoactivity patterns of abomasal smooth
muscle preparations are highly variable and differ on
the basis of location and fiber orientation. Frequency
of contractions differed significantly among time
periods for longitudinally oriented specimens with
decreasing frequencies of contractions over time.
Maximal amplitude of the longitudinally oriented
specimens from the antrum increased significantly,
whereas maximal amplitude of the circularly oriented
specimens from the antrum decreased significantly.
Values did not differ significantly among
Conclusions and Clinical Relevance—Patterns of
spontaneous contractility of abomasal wall specimens
are not homogeneous. During a 4-hour recording
period, maximal amplitude and frequency of contractions
of specimens varied significantly with
respect to orientation and location; however, spontaneous
contractile myoactivity did not differ significantly
among breeds. Therefore, breed predisposition
for displaced abomasum is not correlated with spontaneous
activity of smooth muscle specimens. (Am J
Vet Res 2002;63:1687–1694)