ISSN:
1471-4159
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
Rat cerebral cortex slices were incubated in vitro with [3H]dopamine (DA) or [3H]noradrenaline (NA) (10−7M), superfused by fresh buffer and stimulated by an electric field. The stimulation-induced overflow of [3H]DA and [3H]NA was determined.In slices from untreated rats about 16 ng [3H]NA/g tissue was formed from [3H]DA, corresponding to about 5 per cent of the endogenous NA concentration. Stimulation markedly enhanced the overflow of [3H]NA. The [3H]NA newly formed from [3H]DA was overflowing to a greater extent than [3H]NA previously taken up from the incubation medium, indicating a preferential release of newly synthesized transmitter. The stimulation-induced overflow of [3H]DA and [3H]NA was increased in slices of rats pretreated with a tyrosine hydroxylase inhibitor (H44/68). It seems that depletion of the endogenous NA stores of central NA neurons by tyrosine hydroxylase inhibition makes the [3H]cate-cholamines more available for release. Pretreatment of the rats with the DA-β-hydroxylase inhibitors FLA63 or FLA69 considerably diminished the formation of [3H]NA from [3H]DA. Stimulation markedly enhanced the overflow of [3H]DA indicating that DA can act as a ‘false transmitter’ in central NA neurons after DA-β-hydroxylase inhibition.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1471-4159.1971.tb00205.x
