Regional variation in the response of cerebral ornithine decarboxylase to electroconvulsive shock

Abstract

Levels of ornithine decarboxylase activity were measured in brain regions and in adrenal glands of adult male rats exposed to electroshock. Five hours after shock at levels causing transient loss of consciousness and fore and hindlimb tonic extensor seizures, major increases in ornithine decarboxylase activity were found in adrenals, hippocampus, brain stem, frontal cortex, and cerebellum, but striatal levels were unchanged. These increases were reversed by 24 h after electroshock. When lower levels of shock, which caused no loss of consciousness, were also used, a clear dose-response relationship of shock intensity and ornithine decarboxylase activity was found for hippocampus and brain stem. The ornithine decarboxylase response in brain increased with higher shock levels. However, the changes of ornithine decarboxylase in adrenal glands were maximal at intermediate, and diminished at maximal shock values, as were levels of circulating testosterone. These data suggest a differing role for cerebral and adrenal ornithine decarboxylase in the mature rat. The brain enzyme may be primarily related to metabolic repair processes, whereas adrenal ornithine decarboxylase may function in the activation of secretion.

Targets of polyamine dysregulation in major depression and suicide: Activity-dependent feedback, excitability, and neurotransmission

“…Evidence from the past three decades shows that firing rate and ODC1 activity are tightly correlated across a broad range of excitability levels, from small changes of ODC1 occurring during physiological stimulation of visual pathways, to large increments (≥ 50-fold) during epileptiform activity (Baudry et al, 1986) or electrical stimulation (Bondy et al, 1987; Pajunen et al, 1978). Notably, even small changes in the concentration of polyamines during physiological stimulation can have important modulatory effects on excitatory synaptic inputs that modulate sensory experience (Aizenman et al, 2002), indicating that the polyamine system participates in activity-feedback mechanism that sense and regulate neuronal activity (Fig.…”

Effect of trimethyltin on ornithine decarboxylase in various regions of the mouse brain

“…This regional selectivity has been confirmed in studies of neurotransmitter-related parameters [9][10][11] and provides the opportunity to examine for metabolic changes in various brain areas after exposure of animals to TMT. Ornithine decarboxylase (ODC), the rate limiting enzyme of polyamine synthesis, is capable of rapidly responding in cerebral tissues that have been activated or damaged [12][13][14]. This property of ODC can be used to detect the targets of neurotoxic agents [15).…”

Differential effects of difluoromethylornithine on basal and induced activity of cerebral ornithine decarboxylase and mRNA

“…The extent to which each of these factors are responsible for the fluctuations in the activity of cerebral ornithine decarboxylase is not yet known. Previously, it was found that electroconvulsive shock (ECS) resulted in a region-specific induction of cerebral activity of omithine decarboxylase (Bondy, Mitchell, Rahmaan and Mason, 1987). Some of the cellular and molecular events that accompany the induction of neocortical omithine decarboxylase, in response to electroshock-induced seizures, have been described (Zawia and Bondy, 1990).…”