Distribution of serotonin-immunoreactivity in the central nervous system of the rat-cell bodies and terminals.

Molecular pathways involved in the neurotoxicity of 6-OHDA, dopamine and MPTP: contribution to the apoptotic theory in Parkinson's disease.

Introduction LITTLE IS known about the possible etiological biochemical factors relating to depressive reactions. Clinical evidence suggests that many depressions respond to the following somatic treatment: electric convulsive therapy (ECT), the imipramine type of drugs, and the monoamine oxidase inhibitor group of drugs. 2,3 Do these two classes of drugs have common factors in their mechanism of action and can this be related to the fact that one antihypertensive agent, namely, reserpine, produces severe depression in a small but consistent number of hypertensive patients? 4-8 Rosenblatt et al, 9 in 1959, were among the first to specifically suggest that changes in brain norepinephrine (NEP) may be involved in depression. Based in part on the knowledge of the effect of reserpine and monoamine oxidase inhibitors on depressed mood and norepinephrine (NEP), they hypothesized that the depressive state might be associated with a relative decrease of norepinephrine

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Norepinephrine in Depressive Reactions: A Review

The histochemical fluorescence method of Falck and Hillarp for the demonstration of biogenic monoamines is based on the finding that the amines can be condensed with formaldehyde to yield strongly fluorescent compounds, provided that they are enclosed in a dried protein layer, as in freeze-dried or air-dried tissues. This review deals mainly with certain principal features of the method: its chemistry, sensitivity, specificity and possibilities for histochemical differentiation between the various amines. Some comments are made on certain of the results obtained with this method.

The formaldehyde fluorescence method for the histochemical demonstration of biogenic monoamines a review on the methodology

Immunohistochemical evidence of substance P-like immunoreactivity in some 5-hydroxytryptamine-containing neurons in the rat central nervous system.

The early development of the peripheral adrenergic neurons of the rat was followed with the Falck-Hillarp fluorescence technique. In the 13 day embryo small fluorescent sympathicoblasts with short processes were found in segmentally arranged groups along the dorsal aspect of the embryo. The larger sympathetic ganglia and the strongly fluorescent adrenal medullary cells were easily identifiable at this stage. In the 18 day embryo, fluorescent axon bundles were found in most larger nerve trunks. The outgrowing fluorescent axons had a stronger fluorescence intensity than non-terminal axons of adult animals until at least 2 weeks after birth. The postnatal development of the plexuse of adrenergic nerves was followed in the iris, auricles of the heart, salivary glands, vas deferens and small intestine. The adrenergic innervation of the gut seemed to develop earlier than that of the other organs. Thus, the duodenal muscle layer had a well developed adrenergic innervation of the plexus of Auerbach at birth while the other organs investigated demonstrated well developed networks of adrenergic nerves from about the fourth day on. It was concluded from some pharmacological experiments that, under optimal conditions, the fluorescence technique can reveal all or almost all adrenergic nerves also during early development.

Ontogenesis of Peripheral Adrenergic Neurons in the Rat: Pre‐ and Postnatal Observations

Uptake and accumulation of catecholamines in peripheral adrenergic neurons of reserpinized animals, studied with a histochemical method.

Systemic administration of 5,7-HT to newborn rats produces an altered development of the 5-HT neurons in the central nervous system, with marked regional differences. 5,7-Hydroxytryptamine can enter the brain and elicit its neurotoxic actions after systemic administration in the neonatal stage due to an incompletely developed blood-brain barrier, which for 5,7-HT is elaborated between postnatal Days 5 and 7. Treatment with 5,7-HT at birth produces marked and permanent 5-HT denervation in the cerebral cortex and spinal cord, whereas hyperinnervation occurs in the 5-HT cell body-near regions (mesencephalon-pons-medulla). The latter effect is seen within the first week postnatally. Treatment with 5,7-HT also affects NA neurons in a similar manner, although the action is exerted preferentially on 5-HT neurons. A selective effect on 5-HT neurons can be achieved by DMI pretreatment, after which both NA and DA neurons develop normally. No signs of any interaction among growing 5-HT, NA, and DA neurons can be observed. Studies of the postsynaptic 5-HT receptor in vitro with [3H]-5-HT and [3H]LSD binding indicate that this receptor develops independently of presynaptic 5-HT nerve terminals. Neither 5-HT denervation nor 5-HT hyperinnervation was accompanied by any change in receptor-binding characteristics or receptor density. The results available are compatible with the view that the consequences for 5-HT neurons that occur after neonatal 5,7-HT administration are mainly due to a "pruning effect." The developing 5-HT neurons seem to be programmed to produce a certain quantity of nerve terminal arborizations, which they try to conserve after 5-HT-induced injury, leading to the observed rearrangement of 5-HT nerve terminals.

Developmental plasticity of central serotonin neurons after 5,7‐dihydroxytryptamine treatment*

The postnatal development of noradrenaline uptake in the adrenergic nerves of different tissues from the rat

Die Regenbogenhaut der Maus wurde in einer physiologischen Pufferlosung mit radioaktivem 6-Hydroxydopamin (3H-6-OH-DA) inkubiert. Mit Hilfe autoradiographischer und fluoreszenz-histochemischer Untersuchungen konnte gezeigt werden, dass3H-6-OH-DA in die adrenergischen Nervenfasern der Regenbogenhaut aufgenommen und gespeichert wird. Dieser Befund bringt die direkte Erklarung der durch 6-Hydroxydopamin induzierten Degeneration der adrenergen Fasern.

Ch. Sachs

Papers

Ontogenesis of Peripheral Adrenergic Neurons in the Rat: Pre‐ and Postnatal Observations

Uptake and accumulation of catecholamines in peripheral adrenergic neurons of reserpinized animals, studied with a histochemical method.

Developmental plasticity of central serotonin neurons after 5,7‐dihydroxytryptamine treatment*

The postnatal development of noradrenaline uptake in the adrenergic nerves of different tissues from the rat

Autoradiographic demonstration of uptake and accumulation of 3H-6-hydroxydopamine in adrenergic nerves.