Journal of Neuroscience, Vol 2, 409-414, Copyright © 1982 by Society for Neuroscience
Norepinephrine regulation of cerebral glycogen utilization during seizures and ischemia
SI Harik, R Busto and E Martinez
Norepinephrine (NE) depletion of the cerebral cortex after lesion of the
ipsilateral locus ceruleus (LC) causes abnormalities of cerebral oxidative
metabolism when the cortex is stimulated to increased energy demand (Harik,
S. I., J. C. LaManna, A. I. Light, and M. Rosenthal (1979) Science 206:
69-71; LaManna, J. C., S. I. Harik, A. I. Light, and M. Rosenthal (1981)
Brain Res. 204: 87-101). These abnormalities were exhibited as decreased
mitochondrial reducing equivalent flow. One possible cause of this would be
the decreased availability of oxidative metabolic substrates in the
NE-depleted cortex. We therefore investigated the effect of unilateral LC
lesion and the resultant depletion of ipsilateral endogenous NE on glycogen
and other energy metabolites in the cerebral cortex of rats under three
conditions: (1) at "rest," (2) when energy demand is inncreased markedly by
seizures, and (3) during total cerebral ischemia. We report no differences
in cerebral metabolites between NE-depleted and control hemispheres at
"rest." In seizures and ischemia, however, the increase in the level of
adenosine 3':5'-monophosphate (cyclic AMP) and the breakdown of glycogen
were impaired considerably in the NE-depleted cortex. The data suggest that
depletion of central NE impairs cerebral glycogenolysis in response to
increased energy demands and ischemia. Such impairment may be mediated via
a cyclic AMP-related mechanism.