Japanese Journal of Physiology 

About: Japanese Journal of Physiology is an academic journal. The journal publishes majorly in the area(s): Stimulation & Membrane potential. It has an ISSN identifier of 0021-521X. Over the lifetime, 3551 publications have been published receiving 53461 citations.

Perspectives on pituitary adenylate cyclase activating polypeptide (PACAP) in the neuroendocrine, endocrine, and nervous systems.

Abstract: PACAP is a pleiotropic neuropeptide that belongs to the secretin/glucagon/VIP family. PACAP functions as a hypothalamic hormone, neurotransmitter, neuromodulator, vasodilator, and neurotrophic factor. Its structure has been remarkably conserved during evolution. The PACAP receptor is G protein-coupled with seven transmembrane domains and also belongs to the VIP receptor family. PACAP, but not VIP, binds to PAC1-R, whereas PACAP and VIP bind to VPAC1-R and VPAC2-R with a similar affinity. Despite the sizable homology of the structures of PACAP and VIP and their receptors, the distribution of these peptides and receptors is quite different. At least eight subtypes of PACAP specific, or PAC1-R, result from alternate splicing. Each subtype is coupled with specific signaling pathways, and its expression is tissue or cell specific. Although PACAP fulfills most requirements for a physiological hypothalamic hypophysiotropic hormone, it does not consistently stimulate secretion of the adenohypophysial hormones, except for stimulation of IL-6 release from the FS cells of the pituitary. The major regulatory role of PACAP in pituitary cells appears to be the regulation of gene expression of pituitary hormones and/or regulatory proteins that control growth and differentiation of the pituitary glandular cells. These effects appear to be exhibited directly and indirectly through a paracrine or autocrine action. Although PACAP stimulates the release of AVP, the physiological role of neurohypophysial PACAP remains unknown. One important action of PACAP in the endocrine system is its role as a potent secretagogue for adrenaline from the adrenal medulla through activation of TH. PACAP also stimulates the release of insulin and increases [Ca2+]i from pancreatic beta-cells at an extremely small concentration. The stage-specific expression of PACAP in testicular germ cells during spermatogenesis suggests its regulatory role in the maturation of germ cells. In the ovary, PACAP is transiently expressed in the granulosa cells of the preovulatory follicles and appears to be involved in the LH-induced cellular events in the ovary, including prevention of follicular apoptosis. In the central nervous system, PACAP acts as a neurotransmitter or neuromodulator, which has been supported by IHC and electrophysiological methods. More important, PACAP is a neurotrophic factor that may play an important role during the development of the brain. In the adult brain, PACAP appears to function as a neuroprotective factor that attenuates the neuronal damage resulting from various insults.

Nystatin Perforated Patch Recording and Its Applications to Analyses of Intracellular Mechanisms

Abstract: We have reviewed the basic aspects of history, physicochemical properties, advantages, disadvantages, and applications of nystatin- and amphotericin B-perforated patch recording. Recently, we have developed a novel perforated patch technique using gramicidin [49, 132, 133]. Since gramicidin pores are permeable to Na+ and K+ but not to Cl-, it is possible to maintain the physiological concentration of intracellular Cl- and thereby to measure it in real-time from small neurons. Further improvement of the perforated patch techniques would be possible by limiting redistribution of specific intracellular ions. In light of their broad applicability, the perforated patch techniques will prove indispensable for electrophysiologists working on the functions and modulations of receptors, ion channels and transport phenomena. Research with the perforated patch should continue to provide important information relevant to the physiological and pathological conditions of cells.

Desynchronization of human circadian rhythms

Abstract: Fifty human sub jects have been kept in an underground bunker in conditions of continuous illumination, each in complete isolation and without any time-telling device. Rectal temperature was recorded continuously by means of an electric thermometer, and urine samples, collected in intervals of the subjects own choice, were analyzed for excretion of water, sodium, calcium and potassium. Several systems of electric contacts served to survey the subjects general activities. All subjects showed free-running circadian rhythms, the average periods of wakefulness and sleep ranging from 23.9 to 50.0 hours. 36 subjects remained internally synchronized during the whole experiment. In 5 cases, the rhythm of activity and the rhythms of vegetative functions were synchronized in a 1: 2-ratio for parts of the experiment. 9 subjects showed different circadian frequencies in activity and in body temperature; in two of these subjects, desynchronization started immediately after being enclosed in the bunker, in the remaining 7 subjects after 9 to 23 days of confinement.

A novel fibrinolytic enzyme extracted from the earthworm, Lumbricus rubellus.

Abstract: A strong fibrinolytic enzyme was readily obtained in saline extracts of the earthworm, Lumbricus rubellus. It hydrolyzed not only plasminogen-rich fibrin plates, but also plasminogen-free fibrin plates. The average fibrinolytic activity was about 100 CU (plasmin units) or 250 IU (urokinase units)/g wet weight. The molecular weight and isoelectric point were about 20,000 and 3.4, respectively. The enzyme was heat-stable and displayed a very broad optimal pH range. DFP and SBTI strongly inhibited the enzyme, but the anti-plasmin agent, t-AMCHA, exerted little effect under the same conditions. Purification of the enzyme was performed and three partially purified fractions were obtained. These three fractions were further subdivided. The first fraction (F-I) was divided into three fractions (F-I-0, F-I-1, and F-I-2), which exhibited similar biochemical characteristics. The second fraction (F-II) could not be subdivided. The third fraction (F-III) was divided into two fractions (F-III-1 and F-III-2). Based on results for their enzymatic activities against various substrates, the fraction I enzymes are thought to represent a chymotrypsin-like enzyme and the fraction III enzymes to represent a trypsin-like enzyme. The fraction II enzyme appears to be neither a trypsin- or chymotrypsin-like enzyme nor an elastase. The amino acid compositions of the six enzymes were estimated. Compared with other serine enzymes, these enzymes contained very abundant asparagine or aspartic acid, and there was very little proline or lysine. From the above data, these enzymes are regarded as novel fibrinolytic enzymes, and we name them collectively as Lumbrokinase from the generic name of the earthworm.