Regional cerebral palmitate incorporation after unilateral auditory deprivation in immature and adult Fischer-344 rats.

Regional cerebral incorporation of intravenously injected [U-14C]palmitate was measured from 1 day to 13 weeks after left cochlear destruction in 11-day- and 3 month-old, awake Fischer-344 rats. In 11-day-old animals, statistically significant left-right differences in incorporation were absent 1 day after cochlear destruction and were found only in parts of the cochlear nucleus and inferior colliculus after 1 week. After 6 to 13 weeks, consistent with functional neuroanatomy of central auditory regions, incorporation was reduced by 6 to 9% in the left cochlear nucleus and left lateral superior olivary nucleus, compared with corresponding right-side regions. The right medial superior olivary nucleus, medial nucleus of the trapezoid body, lateral lemniscus nucleus, inferior colliculus, medial geniculate body, and auditory cortex had 5 to 9% less incorporation than did corresponding left-side regions. Fewer significant differences after chronic auditory deprivation occurred in 3-month-old rats than in 11-day-old rats following cochlear destruction. Reduced incorporation corresponded to reported changes in cell morphology, which also were greater in immature than mature rats following auditory deprivation. The results suggest that the palmitate method can be used to identify long-term regional changes in the turnover of brain lipids after sensory deprivation.