Existence and localization of adrenergic neurons in meninges from human adults and fetuses

✓ The cerebral and cerebellar pia mater and arachnoid of 90 adults and 15 fetuses have been studied in order to determine whether the number of arachnoidal neural elements is sufficiently high to dismiss the possibility of their being purely heterotopic or displaced structures. With the aid of various histological techniques and formaldehyde (noradrenaline)-induced fluorescence, the presence of a reticulum composed of many short adrenergic neurons was demonstrated, intimately associated with the sympathetic perivascular innervation. Although this network seems to participate in some aspects of peripheral neuroendocrine function, its possible role in physiologically or pathologically regulating cerebral blood flow is as yet unsettled.

Regional distribution of autonomic nerves in guinea pig uterus

Uterine adrenergic and cholinergic nerves were examined histochemically and chemically in combination with surgical denervation. There was a clear regional variation with a greater number of axon terminals in the tubal end of the uterine horn and in the cervix compared to the remainder (major part) of the uterine horn. No cholinergic nerves were found in the uterus but were abundant around the uterine artery and its primary ramifications. Clusters of ganglion cells were located near the cervix: the majority were acetylcholinesterase positive, whereas the remainder stored catecholamines. Unexpectedly, the suspensory ligament (connecting the tubal end of the uterine horn with the two lower ribs) was found to contain an extensive number of adrenergic nerves. The major part of the uterine horns, as well as the cervix, was innervated mainly from two sources contributing almost equally: the paracervical ganglia (short adrenergic neurons) and postganglionic fibers running in the hypogastric nerves. A restricted area at the tubal end of the uterus received most of its via the suspensory ligament.

Effect of serotonin on brown adipose tissue and on its sympathetic neurons

Previously we have shown that there are two types of sympathetic neurons in the rat interscapular brown fat-pad: long adrenergic neurons with cell bodies located in the paraspinal ganglia and short adrenergic neurons with cell bodies located within the pad itself. The present studies examine 1) the uptake of [3H]norepinephrine by these neurons, 2) the effect of serotonin on release of the catecholamine, and 3) the metabolic action of serotonin on brown fat. [3H]norepinephrine uptake from the medium in which brown fat slices are incubated is linear with time up to 90 min. This uptake is blocked by both cocaine and imipramine. As these drugs block uptake by sympathetic neurons, the [3H]norepinephrine is probably taken up by neurons and not by some other cell in the pad. Serotonin creatinine sulfate, but not creatinine sulfate, promotes the release of the catecholamine from these neurons. Serotonin also exerts a norepinephrine-like metabolic effect on slices of normal brown fat. It stimulates lipolysis and inhibits lipogenesis. Serotonin has no effect on isolated brown fat cells or on slices of reserpinized tissue. It also does not potentiate the action of norepinephrine on these last two preparations. Therefore serotonin's action on brown fat is mediated by norepinephrine-containing stromal cells. The data suggest that the rat brown fat-pad has sympathetic neurons that can take up norepinephrine and that serotonin exerts its metabolic effect by stimulating the release of norepinephrine from these neurons.

EFFECT OF HIGH DOSES OF OESTROGEN AND PROGESTERONE ON THE NORADRENALINE CONTENT OF THE SHORT ADRENERGIC NEURONS INNERVATING THE MALE GENITAL TRACT OF THE RAT

ABSTRACT The effect of prolonged treatment with high doses of oestrogen and/or progesterone on the amount of adrenergic transmitter in the short adrenergic neurons of the male reproductive tract of castrated rats has been studied by chemical determinations and histochemical demonstration of noradrenaline. Oestrogen, progesterone, or a combination of both, had no overt effect on the total content or on the concentration of noradrenaline in the male genital organs. The results are discussed in the light of recent findings that the content of the noradrenaline transmitter in the short adrenergic neurons to the female genital tract is markedly influenced by these female sex hormones.