CEREBRAL METABOLISM FOLLOWING NEONATAL OR ADULT HEMINEODECORTICATION IN CATS .1. EFFECTS ON GLUCOSE-METABOLISM USING [C-14] 2-DEOXY-D-GLUCOSE AUTORADIOGRAPHY
Da. Hovda et al., CEREBRAL METABOLISM FOLLOWING NEONATAL OR ADULT HEMINEODECORTICATION IN CATS .1. EFFECTS ON GLUCOSE-METABOLISM USING [C-14] 2-DEOXY-D-GLUCOSE AUTORADIOGRAPHY, Journal of cerebral blood flow and metabolism, 16(1), 1996, pp. 134-146
In the cat, cerebral hemispherectomy sustained neonatally results in a
remarkable degree of recovery and/or sparing of function as compared
with the effects of a similar lesion but sustained in adulthood. We ha
ve proposed that this effect is due to a combination of reduced neuron
al loss within partially denervated structures and a lesion-induced re
organization of corticofugal projections arising from the remaining in
tact hemisphere in the neonatally lesioned animal. The current study w
as designed to assess the physiological consequences of these anatomic
al changes utilizing [C-14]2-deoxy-D-glucose autoradiography. A total
of 17 adult cats were studied. Seven animals served as intact controls
, five received a left cerebral hemineodecortication as neonates (NH;
mean age 11.4 days), and five sustained the same lesion in adulthood (
AH). Histological analysis indicated that the lesion was very similar
between the two age groups and essentially represented a unilateral he
mineodecortication. Local CMR(glc) (LCMR(glc); mu(m)ol 100 g(-1) min(-
1)) values were calculated for 50 structures bilaterally and indicated
that in the remaining intact contralateral (right) cerebral cortex (i
ncluding all areas measured), AH cats exhibited a significantly (p < 0
.05) lower level of LCMR(glc) (ranging from 20 to 72 mu mol 100 g(-1)
min(-1)) than NH (ranging from 49 to 81 mu mol 100 g(-1) min(-1)). In
comparison, the rates of NH cats within the cerebral cortex were very
similar to those seen in intact animals (ranging from 48 to 119 mu mol
100 g(-1) min(-1)). Ipsilateral to the lesion in AH cats, the structu
res spared by the resection, including the basal ganglia and thalamus,
exhibited LCMR(glc) rates of between 23 and 69 mu mol 100 g(-1) min(-
1), which were significantly lower (p < 0.05) than in NH cats (range 4
7-72 mu mol 100 g(-1) min(-1)). Considering all structures, both age-a
t-lesion groups exhibited a lower level of metabolism compared with si
milar measurements for intact control animals (LCMR(glc) range 45-75 m
u mol 100 g(-1) min(-1)). However, this depression of glucose metaboli
sm was more pronounced in the AH cats (p < 0.05). These results indica
te that following neonatal hemineodecortication, LCMR(gl)c is maintain
ed at a higher level in many regions of the brain than in animals that
sustain the same resection in adulthood. This higher level of glucose
metabolism in NH animals suggests that the lesion-induced anatomical
reorganization of structures not directly injured by the lesion plays
a functional role that is probably responsible for the greater degree
of recovery and/or sparing of function in these early lesioned cats.