Cholinergic and noradrenergic denervations decrease labelled purine release from electrically stimulated rat cortical slices.
The origin of cortical purine release was investigated by measuring [3H]purine release from electrically stimulated cortical slices of rats after neurotoxic lesions of cholinergic, noradrenergic and serotoninergic pathways innervating the cortex. Purines were labelled by incubating the cortical slices with [3H]adenine. The 3H efflux at rest and during stimulation, analysed by high performance liquid chromatography, consisted of adenosine, inosine, hypoxanthine and a small amount of nucleotides. Twenty days after unilateral or bilateral lesion of the nucleus basalis a marked decrease in choline acetyltransferase activity was associated with a decrease in [3H]purine release. A linear relationship was found between the decrease in choline acetyltransferase activity and [3H]purine release. A partial recovery in both choline acetyltransferase activity and [3H]purine release was observed eight months after the lesion. Twenty days after intra-cerebroventricular injection of 6-hydroxydopamine a 59% decrease in cortical noradrenaline content was associated with a 44% decrease in [3H]purine release. Conversely, no change in [3H]purine release was found in rats in which a 89% decrease in cortical serotonin content was induced by intra-cerebroventricular injection of 5,7-dihydroxytryptamine. The decrease in [3H]purine release after the lesion of the cholinergic and noradrenergic pathways may depend on metabolic changes, a loss of a stimulating influence of acetylcholine and noradrenaline or may indicate a release of [3H]purine from cholinergic and noradrenergic fibres.
Pedata
F
F
Department of Preclinical, University of Florence, Italy.
Di Patre
P L
PL
Giovannini
M G
MG
Pazzagli
M
M
Pepeu
G
G
D000241:Adenosine / Q000378:metabolism; D000320:Adrenergic Fibers / Q000201:enzymology / Q000502:physiology*; D000818:Animals; D001479:Basal Ganglia / Q000502:physiology*; D002540:Cerebral Cortex / Q000378:metabolism* / Q000502:physiology; D002795:Choline O-Acetyltransferase / Q000378:metabolism; D002799:Cholinergic Fibers / Q000502:physiology*; D004558:Electric Stimulation; D019271:Hypoxanthine; D007042:Hypoxanthines / Q000378:metabolism; D007051:Ibotenic Acid; D007288:Inosine / Q000378:metabolism; D008297:Male; D009410:Nerve Degeneration; D011687:Purines / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D007042:Hypoxanthines; D011687:Purines; D007051:Ibotenic Acid; D019271:Hypoxanthine; D007288:Inosine; D002795:Choline O-Acetyltransferase; D000241:Adenosine