The relation between capillaries and neurons in the caudal neurosecretory system ofPomatomus saltatrix

Summary The caudal neurosecretory system ofPomatomus saltatrix was examined. Particular interest was devoted to the perikarya of the neurosecretory cells. The majority of these cells were characterized by a close association with the capillary network. The cells appeared to ensheath the capillaries thus bringing the nucleus and perinuclear cytoplasm into close association with the capillaries.Supported byA. D. Williams No. 3558 (505), Medical College of Virginia. The authors are grateful to Dr.H. R. Seibel for reading this report.     

On the significance of the rostral process of bipolar neurosecretory cells in the caudal neurosecretory system of certain catfishes

Neurosecretory substance has been identified in the rostral process of bipolar neurosecretory cells of the caudal neurosecretory system in 4 Indian catfishes, using acid violet stain. The role of the rostral process in the transmission of the neurosecretory substance is discussed.     

On the significance of the rostral process of bipolar neurosecretory cells in the caudal neurosecretory system of certain catfishes

Summary Neurosecretory substance has been identified in the rostral process of bipolar neurosecretory cells of the caudal neurosecretory system in 4 Indian catfishes, using acid violet stain. The role of the rostral process in the transmission of the neurosecretory substance is discussed.We thank Prof. U.S. Srivastava, Allahabad University, for laboratory facilities and useful suggestions. The U.G.C. financial assistance under the Faculty Improvement Programme, to one of us (H.C.S.) is gratefully acknowledged.     

The neurosecretory system of the octopus vena cava: A neurohemal organ

Summary Endings of about two million small neurones form a voluminous neuropil inside the vena cava of cephalopods, in direct contact with the blood. These nerve endings are filled with masses of typical neurosecretory granules. By immunocytochemistry we could distinguish three different populations of secretory endings in the vena cava neuropil ofOctopus vulgaris: 1) a population of endings which were immunoreactive with antibodies against the pentapeptide proctolin; 2) a population with oxytocin/vasopressin- and neurophysin-like immunoreactivity; 3) a population immunoreactive with antibodies which were raised against the molluscan cardioexcitatory peptide Phe-Met-Arg-Phe-amide, against -melanotropin, and against atriopeptin. Extracts of the octopus vena cava stimulated amplitude and frequency of the isolated octopus heart preparation. Similar effects were exerted by peptides with the C-terminal structure-Arg-Phe-amide. Recently, we could isolate and identify in vena cava extracts four peptides; Phe-Met-Arg-Phe-amide, Phe-Leu-Arg-Phe-amide, Ala-Phe-Leu-Arg-Phe-amide and Thr-Phe-Leu-Arg-Phe-amide. Other peptides have not yet been identified. The fact that the peptides against which the immunoreactive antibodies were raised affected, in different organisms, blood volume, blood pressure, renal function and heart contraction suggests that one of the main functions of the neurosecretory system of the vena cava is a hormonal control of circulation.     

A new neurosecretory system in fish,located in the gill region

Summary A peculiar neurosecretory system is reported in 6 teleost species;Clarias batrachus, Heteropneustes fossilis, Mystus seenghala, Ompak pabda, Glassogobius giuris andNotopterus notopterus. It is located in the gill region close to the pseudobranch or to the carotid labyrinth. The neurosecretory cells have been identified using stains specific for neurosecretion. The results are discussed in the light of the association of the neurosecretory system with the pseudobranch or the carotid labyrinth, and the airbreathing habit of these fishes.We are grateful to Prof. U.S. Srivastava for providing laboratory facilities and for encouragement. The work was financially supported by U.G.C. Research Project grant awarded to C.B.L.S., which is thankfully acknowledged. Thanks are due to M. Seal and Amarlata for technical help rendered.     

The relation between gamma motor activity and the electroencephalogram

Zusammenfassung Es wurde gezeigt, dass die Weckreaktion im EEG meist mit Erregung der Muskelspindeln verknüpft war. In tieferer Narkose konnten die Muskelspindeln bei Erwärmung des Hypothalamus noch beeinflusst werden, ohne dass im EEG nennenswerte Veränderungen auftraten. Thermische Reizung im Hypothalamus konnte aber auch bei der «encéphale isolé»-Katze langsame, grosse Wellen in Grosshirnrinden-Ableitungen hervorrufen. Wahrscheinlich werden die Muskelspindeln und die Aktivität der Grosshirnrinde dabei über dasselbe System vom Hirnstamm beeinflusst.     

Demonstration of a 2d LH-RH neurosecretory system in the duck hypothalamus]

Using immunocytochemical techniques with an anti-LH-RH immuneserum, evidence of two neuronal systems secreting LH-RH has been shown in the Duck hypothalamus. In addition to the previously described system, located in the preoptic nucleus, a second system could be demonstrated in the infundibular nucleus. The perikarya of the infundibular LH-RH producing neurons were significantly smaller than those of the preoptic neurons. On the other hand, under the experimental conditions used, the infundibular system had approximately five times less LH-RH secreting neurons than the preoptic system, and its perikarya appeared less heavily loaded in IR LH-RH. The LH-RH containing axons from both neuronal populations ran down to the external layer of the median eminence, where they ended in close contact with the capillaries of the hypophysial portal system.     

Immunocytochemical localization of hyperglycemic hormone (HGH) in the neurosecretory system of the eyestalk of the crayfish Astacus leptodactylus.

Hyperglycemic hormone (HGH) from Astacus leptodactylus can be visualized by an immunocytochemical procedure using a specific antiserum against HGH and the peroxidase-anti-peroxidase (PAP) method. HGH containing cells are localized in the most distal portion of the x-organ in the medulla terminalis. Their cell diameter is about 47 +/- 7 micrometer; the nucleus measures about 22 +/- 2 micrometer. They form a subgroup of neurosecretory cell type 1, already described for the crayfish. A large amount of this HGH material is homogeneously stored in the sinus gland. A group of fibres in the x-organ - sinus gland - tractus can be followed, due to their positive reaction with the PAP-reagent.     

The relation between the bicarbonate concentration in blood plasma and in brain tissue

Zusammenfassung Die Frage des passiven Transportes von HCO ₃ ^– - und H⁺-Ionen zwischen Blutplasma und Gehirngewebe wurde untersucht. Die Blutkonzentration dieser Ionen wurde durch intraperitoneale Injektionen variiert und der Gesamt-CO₂-Gehalt des Gehirngewebes nach 1–12 h bestimmt. Es ergab sich keine signifikante Änderung im Gesamt-CO₂-Gehalt des Gewebes, obwohl der Standardbikarbonatgehalt des Blutes mit 10–13 mE/l verändert wurde.     

Differences in the numbers of fenestrae between the arterial and venous ends of capillaries in the adrenal cortex

Résumé Dans le cortex adrénal des souris les limbes des capillaries vieneux ont 4.3 fenestrae endothéliales de plus que les limbes artériels. On estime que cette pré-pondérance des fenestraes vieneuses, qui se retrouve ailleurs, et très importante et permet à celles-ci d'enlever du tissu les grandes molécules extravasculaires.     

The ischemic and postischemic effect on the uptake of neutral amino acids in isolated cerebral capillaries.

The uptake of some neurtral amino acids was investigated in cerebral microvessels isolated from brains of gerbils subjected to bilateral cerebral ischemia with and without various periods of recovery. A transiently increased capillary uptake of 3H-isoleucine, 14C-cycloleucine and 3H-phenylalanine was found in both conditions.     

Control of the cardiovascular system of Aplysia by identified neurons.

The neural network that controls the cardiovascular system of Aplysia adapts cardiovascular function to a variety of different physiological and behavioral situations. It (1) coordinates the cardiovascular system with the renal and respiratory systems; (2) modifies both systemic and regional blood flow during food-elicited arousal and feeding; and (3) changes the tension of longitudinal vascular muscle to adapt the arterial tree to changes in body shape. Indirect evidence suggests that the cardiovascular control circuit may also play a role in maintaining homeostasis during egg laying. Several putative neurotransmitters, including acetylcholine, serotonin, R15 alpha 1 and R15 alpha 2 peptides, have been localized to identified neurons in this circuit.     

The relation between electrical self-stimulation sites and catecholamine-containing neurones in the rat mesencephalon

Résumé 72 électrodes implantées dans les mésencéphales des rats ont été examinées pour le comportement d'autostimulation. La majorité des sites positifs entourait le noyau interpédonculaire où se situent des neurones dopaminiques.

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Supported in part by grants from the U.K. Medical Research Council and the Mental Health Research Fund.