Immunohistochemical demonstration of neurophysin in the hypothalamoneurohypophysial system

Histological, histochemical, ultrastructural and immunohistochemical identification and characterization of the neurosecretory cells of the adult rabbit's adrenal medulla

The present investigation was conducted on the adrenal glands of 40 adult New Zealand rabbits of both sexes to characterize and identify the histological, histochemical, ultrastructural, and immunohistochemical features of the neurosecretory cells of the adrenal medulla. The obtained specimens of adrenal medulla were subjected to routine histological techniques and then stained with different histological stains, including general, non-specific, specific, and highly specific stains for neurosecretory cells, in addition to immunohistochemical reactions. The obtained results showed two types of adrenal medullary neurosecretory cells containing secretory granules (SGs) of different electron densities: adrenaline and noradrenaline (NA) secreting cells. These secretory granules showed a strong positive reaction to the Grimelius silver impregnation technique. Sections stained with Gomori's chrome alum haematoxylin stain, and the secretory granules showed a strong dark blackish-blue positive colour. The medullary cells showed typical chromaffin reactions when stained by H&E and Giemsa stains after formol dichromate 'Ortha's fluid' fixation. The noradrenaline secretory granules gave a strong positive Schmorl's test, while the adrenaline ones showed a moderate reaction. Immunohistochemically, the adrenal medullary cells were subjected to anti-chromogranin A (CHGA) antibody using the PAP technique, which gave positive reactions.

The neurophysin-containing innervation of the forebrain of the mouse

The oxytocinergic and vasopressinergic innervation of the forebrain of normal mice was studied immunocytochemically by use of a set of mouse monoclonal anti-neurophysins applied to serial vibratome sections. The extensive hypothalamic and extra-hypothalamic location of these neuropeptides was revealed, with, or without colchicine pretreatment. Magnocellular perikarya immunoreactive for either oxytocin-neurophysin or vasopressin-neurophysin were concentrated mainly: in the anterior commissural nucleus; in various subdivisions of the paraventricular nucleus; in a profuse array in the periventricular region; in the supraoptic nucleus including its retrochiasmatic division; in various accessory nuclei; and as a number of cells scattered throughout the preoptic and hypothalamic regions. Extensive groups of parvocellular neurons, containing only vasopressin-neurophysin, were located in the suprachiasmatic nucleus including a ventromedial division, in the bed nucleus of the stria terminalis, and in the medial amygdaloid nucleus. Perikarya in the magnocellular nuclei were of generally similar size distribution and there was no evidence that distinct populations of magnocellular and parvicellular neurons, separable on the basis of size, had been labelled within these nuclei. Within the paraventricular nucleus, however, neurons in the posterior part were smaller than those located more anteriorly, and the cells containing oxytocin-neurophysin were slightly smaller than those containing vasopressin-neurophysin. Within the generally similar size distribution, magnocellular neurons of the anterior commissural nucleus were the largest. During processing, shrinkage of the tissue and immunolabeled cells had occurred. The immunocytochemical procedure delineated neuronal processes, in particular dendrites, very effectively. The dendrites were shown to project for far greater distances than is generally recognized, some were of a characteristic corkscrew-like morphology, and most were oriented in a well-defined pattern. Many dendrites of paraventricular neurons passed medially than caudally towards and then along the third ventricle. Most dendrites of supraoptic neurons, in particular those containing vasopressin-neurophysin, had an extensive anteroposterior course beneath the pia of the base of the brain. The axons containing oxytocin- and vasopressin-neurophysin were shown to take rather different paths from the paraventricular nucleus towards the median eminence.(ABSTRACT TRUNCATED AT 400 WORDS)

Presence of neurophysin-like material in the pituitary corticotrophs and melanotrophs and cells of the arcuate nucleus of the rat as revealed by immunocytochemistry

Highly purified porcine neurophysin-II, prepared from pig posterior pituitary lobe tissue was injected into fifteen rabbits in the preparation of anti-neurophysin sera. All antisera, when used in association with immunohistochemical procedures, gave an immunoreaction in structures of the rat hypothalamo-neurohypophysial system. Four antisera, however, also stained cells of the arcuate nucleus, corticotrophs and melanotrophs. Staining of the latter two cell groups also occurred in tissues obtained from Brattleboro rats. Preadsorption of the latter neurophysin antisera with either alpha-MSH, beta-LPH, beta-endorphin, ACTH (1-24), ACTH (17-39), ACTH (1-39), gastrin and CCK, failed to inhibit the staining of the corticotrophs, melanotrophs and cells of the arcuate nucleus. Inhibition of staining was achieved only by preadsorption of the antineurophysin sera with the neurophysin antigen or an homogenate prepared from the anterior pituitary. These results support the observation by others that the biosynthesis of the ACTH-beta-endorphin system in the pituitary and hypothalamus may also be accompanied by the appearance of neurophysin.

Oxytocin, vasopressin, and estrogen-stimulated neurophysin: daily patterns of concentration in cerebrospinal fluid

The concentrations of oxytocin, arginine vasopressin, and estrogen stimulated neurophysin in cerebrospinal fluid of monkeys showed a daily fluctuation with high concentrations occurring during the light period. The patterns of oxytocin and estrogen-stimulated neurophysin in the cerebrospinal fluid were not observed in the plasma nor were they altered after the administration of a dose of estradiol that increased concentrations of estrogen-stimulated neurophysin in plasma. The disassociation between these cerebrospinal fluid and plasma patterns and values suggests that the secretory activity of neurons that release estrogen-stimulated neurophysin and oxytocin into the cerebrospinal fluid is controlled by mechanisms different from those that control their release into the plasma.

Additional forebrain regions projecting to the posterior pituitary: preoptic region, bed nucleus of the stria terminalis, and zona incerta

Following the injections of horseradish peroxidase (HRP) into the posterior lobe of the pituitary gland of adult albino rats, scattered retrogradely labeled neurons were observed in the caudal part of the bed nucleus of the stria terminalis (ventrally and laterally), in the median and periventricular preoptic nuclei, in the medial and lateral preoptic areas, in the zona incerta, and in the substantia innominata. Immunohistochemical studies indicate that oxytocin-containing, or a mixture of vasopressin- and oxytocin-containing neurons are present in each of these areas. These findings suggest that the cells of the magnocellular neurosecretory system are more widely distributed than has previously been reported.

Projections from the paraventricular nucleus to the zona externa of the median eminence of the rhesus monkey: an immunohistochemical study

Immunoperoxidase techniques and light microscopy were used to investigate the origin of the fibers containing vasopressin, oxytocin and related neurophysins (neurohypophyseal peptides), in the zona externa of the median emience of the rhesus monkey. Unilateral lesions were produced in the paraventricular nucleus using a modified Halasz-type knife. Complete destruction of the paraventricular nucleus resulted in a total depletion of all four neurohypophyseal peptides in the ipsilateral zona externa of the median emience. Partial lesions of different segments of the paraventricular nucleus resulted in depletion in different parts of the zona externa. These observations indicate that the paraventricular nucleus is the source of vasopressin, oxytocin and neurophysin in axons which end in the zona externa of the median eminence. These projections are strictly ipsilateral and arranged topographically, so that the more caudal paraventricular neurons project to the dorsal part of th zona externa and the rostral ones to the ventral segment. The supraoptic nucleus does not appear to project to the zona externa, and sends the great majority of its fibers to the neurohypophysis.

Histochemical and immunohistochemical properties of the CRF-granules and other "Gomori-positive" substances of the rat

In adrenalectomized rats, histochemical and immunohistochemical properties of the following secretion products have been investigated: 1. CRF-granules in the outer layer of the median eminence; 2. neurosecretory material (NSM) in the supraoptico-hypophysial system of the hypothalamus; 3. secretory granules in the TSH-cells of the anterior lobe of the hypophysis; 4. secretory granules in the ependymal cells of the subcommissural organ (SCO); 5. beta-cell-granules in the islets of Langerhans in the pancreas. All these substances are characterized by their stainability with the so-called "Gomori method". The experiments have included studies into: a) the extractability of the substances by various solvents; b) the digestability of the substances by pepsin or trypsin; c) their histochemically detectable content of disulfide groups, arginine and periodic acid-Schiff (PAS) reactive carbohydrates; d) their reaction with porcine-neurophysin-II-antibodies. All substances exhibited a positive reaction for disulfide groups. Based on their solubility properties, their resistance to pepsin or trypsin, their respective content of PAS-reactive carbohydrates and their failure to react with anti-neurophysin serum the "Gomori-positive" granules in TSH-, SCO- and pancreatic beta-cells can be distinguished from one another and from CRF- and neurosecretory granules. In contrast, CRF-granules and NSM showed identical properties. Taking into consideration data from the biochemical and histochemical literature, the present findings suggest that CRF-granules and NSM consist of closely related biochemical substances.

Immunocytochemical identification of neurophysin-secreting neurons in the hypothalamo-neurohypophysial system of some non-mammalian vertebrates

Antiserum raised against a mammalian neurophysin, porcine neurophysin-II, was used in conjugation with the immunoperoxidase histochemical technique to detect neurophysin in the hypothalamus of the chickens, frog and goldfish. In the chickens, the paraventricular and supraoptic nuceli as well as the internal and external zones of the median eminence stained for neurophysin. Material in the perikarya of the frog and goldfish preoptic nucleus also cross-reacted immunologically against anti-porcine neurophysin-II serum. Serial dilutions of the anti-mammalian neurophysins serum were carried out in order to ascertain at which point the 3-layer immunocytochemical reaction ceased to localize neurophysin. In the chicken, frog and goldfish as well as in the rat, neurosecretory structures became difficult to visualize between 12800 and 25400 fold dilution of antiserum. The results demonstrate that the immunological cross-reactivity previously observed between an anti-mammalian neurophysin serum and the neurophysin isolated from mammals of varying phylogeny also extends to certain non-mammalian vertebrates and is suggestive of a structural homology of neurophysin from different species.