Extracellular cAMP accumulation and degradation in rat cerebral cortex in dissociated cell culture.
نویسندگان
چکیده
Norepinephrine (NE) stimulated the accumulation of cAMP in embryonic rat cerebral cortex in dissociated cell culture. After exposure to NE for 10 min, the intracellular cAMP content of these cultures went from 22 +/- 12 to 202 +/- 75 pmol/mg protein. Using selective culturing techniques, evidence was obtained supporting the hypothesis that NE-stimulated production of cAMP is a property associated with the glial rather than the neuronal component of these cultures. Beta adrenergic agonist stimulation of cortical cultures also resulted in the efflux of cAMP into the medium. At the peak of extracellular accumulation of cAMP (following a 40-min exposure to isoproterenol), 180 pmol cAMP/mg protein had been transported into the extracellular medium. The fate of extracellular cAMP was investigated using thin-layer chromatography. Extracellular cAMP was degraded to AMP and adenosine; this degradation did not seem to be due to the presence of serum or serum components, suggesting the existence of an extracellular phosphodiesterase. In response to NE stimulation of glia, in particular astrocytes, cAMP or its metabolites may accumulate at high enough concentrations in the extracellular space in cerebral cortex to affect neuronal function, possibly via adenosine receptors.
منابع مشابه
Effect of Paraoxon on GABA Uptake by Rat Cerebral Cortex Synaptosomes
Background: It has been suggested that organophosphates may inhibit gamma-aminobutyric acid (GABA) metabolism in synaptosomal preparations. In the present investigation, we have assessed the interaction between paraoxon and the GABA system at synaptic level. Methods: Synaptosomes were prepared from male Wistar rats (200-250 g). Cerebral cortex was dissected and homogenized, then centrifuged at ...
متن کاملBeta-adrenergic receptor-mediated regulation of extracellular adenosine in cerebral cortex in culture.
Adenosine is an important inhibitory neuromodulator in the CNS, yet the sources of extracellular adenosine have yet to be well characterized. In this study we show that beta-adrenergic stimulation of cortical cultures results in the extracellular accumulation of cAMP as well as adenosine, and that the extracellular adenosine derives from extracellular cAMP. The concentration dependence of isopr...
متن کاملEffect of paraoxon on the synaptosomal GABA uptake in rat hippocampus and cerebral cortex
Introduction: Paraoxon (the neurotoxic metabolite of organophosphorus (OP) insecticide, parathion) exerts acute toxicity by inhibition of acetylcholinesterase (AChE), leading to the accumulation of acetylcholine in cholinergic synapses and hence overstimulation of the cholinergic system. Since, reports on changes in the level of γ- amino butyric acid (GABA) during OP-induced convulsion have bee...
متن کاملThe effect of ibotonic acid lesion of the nucleus basalis of Meynert (NBM) on the response of cortical neurons in the rat barrel cortex
In the present study, the effect of NBM lesion on the temporal characteristics of response integration evoked by multiple whisker stimulations in the barrel cortex of rats was studied. Nucleus basalis of Meynert (NBM) projects to widespread areas of the cortex and provides the major cholinergic input (80%) to the cerebral cortex. In this study we examined the effects of NBM lesion on the respon...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- The Journal of neuroscience : the official journal of the Society for Neuroscience
دوره 9 8 شماره
صفحات -
تاریخ انتشار 1989