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Biomedical subjects

M Fillenz

Publications and source records attributed to M Fillenz.

10 recordsLinked to original sources
PubMed1979

Effect of runway training on rat brain tyrosine hydroxylase: differential effect of continuous and partial reinforcement schedules.

Previous experiments have implicated ascending noradrenergic systems in the development of the behavioural responses to different patterns of reward. In this report food deprived male Sprague--Dawley rats were trained to run a straight alley for good reward on a continuous reinforcement (CRF) or a partial reinforcement (PRF) schedule. Tyrosine hydroxylase measured in a partially solubilized preparation from hippocampus and hypothalamus at the end of acquisition was not different from controls, indicating that enzyme induction does not occur during either training schedules. However, hippocampal synaptosomal tyrosine hydroxylation rates from the CRF group was significantly higher than from either the PRF group or the handled controls. This indicates that at the end of the acquisition schedule the noradrenergic projection to hippocampus was more active in the CRF group than with the PRF group or the handled control.

Animals↗
PubMed1979

Noradrenaline release in rats during prolonged cold-stress and repeated swim-stress.

1 Plasma noradrenaline concentration in rats was measured during prolonged cold-stress and repeated swim-stress. 2 Cold exposure for 6 h caused a rise in plasma noradrenaline which reached a peak at 4 h. 3 Administration of desmethylimipramine and normetanephrine to block neuronal and extra-neuronal uptake of noradrenaline raised plasma noradrenaline concentration without changing the pattern of the response to cold exposure. 4 Repeated cold exposure on subsequent days produced no change in the pattern of plasma noradrenaline concentration. 5 Five successive 1-min swims at 30-min intervals caused a rise in plasma noradrenaline concentration which was maximal after the third swim. 6 It is suggested that prolonged and repeated activation of sympathetic nerve terminals leads to a decline in noradrenaline release.

Animals↗
PubMed1978

Changes in plasma noradrenaline concentration as a measure of release rate.

1 A method is described for repeated sampling of plasma noradrenaline (NA) in freely moving rats. Na concentration does not change during the day or after adrenalectomy. 2 Exogenous NA has a half-life of 1.5 min; drugs which block neuronal and extra-neuronal uptake lengthen this to 6.3 min. 3 Swim-stress leads to a steep rise followed by a rapid decline in plasma NA concentration. 4 This method of plasma NA sampling can serve as a measure of both steady and rapid changes in release rate over long periods of time.

Adrenalectomy↗
PubMed1976

Selective uptake and retrograde axonal transport of dopamine-beta-hydroxylase antibodies in peripheral adrenergic neurons.

In the present experiments the uptake and retrograde axonal transport of antibodies to dopamine beta-hydroxylase (DBH) in adrenergic neurons was studied. When partially purified labelled antibodies to DBH were injected unilaterally into the vicinity of the adrenergic nerve terminals in the iris, radioactive substances accumulated preferentially in the superior cervical ganglia of the injected. By SDS (sodium dodecyl sulfate) gel electrophoresis and immunoprecipitation it could be shown that the accumulated radioactivity in the superior cervical ganglion represented antibodies to DBH. This retrograde accumulation was greatly reduced by colchicine, axotomy or destruction of the adrenergic nerve terminals by 6-hydroxydopamine. The rate of retrograde transport was the same as that of nerve growth factor (NGF) and tetanus toxin in sympathetic neurons. The retrograde transport of antibodies was confined to sympathetic neurons and could not be detect in either sensory or motor neurons.

Animals↗