Effects of brain histamine depletion on stimulated prolactin release in rats

We examined the effects of an irreversible inhibitor of brain histamine (HA) synthesis, -fluoromethyl-histidine (-FMH), on prolactin (PRL) release induced by an opiate agonist (morphine, M) or by a serotonergic agonist (MK212). -FMH was administered intracerebroventricularly (i.c.v., 200 g/rat) into freely moving rats with indwelling catheters in the carotid. M (6 mg/kg, intracarotid, i.a.) was administered simultaneously with or 3 h after -FMH. MK212 (2.5 mg/kg, i.a.) was administered 3 h after -FMH. Blood samples for assay for PRL were drawn at 0, 10, 20, 40 min after M or MK212 administration. -FMH (3 h before) significantly reduced the PRL-releasing effect of M and MK212 but did not modify PRL release by M when administered simultaneously. The present results showing that the facilitatory actions of the opiate and serotonergic systems on PRL are impaired when brain HA synthesis is reduced, suggest that there is an HA-dependent step in opiate and serotonergic control of PRL.     

Inhibition of histamine synthesis influences the development of hypertension in spontaneously hypertensive rats

Young (3-week old) and adult (7-week old) spontaneously hypertensive rats (SHR) and normotensive rats (WKY) were treated with -fluoromethylhistidine (-FMH) for 29 and 13 days, respectively. Treatment of SHR and WKY with -FMH led to a pronounced decrease in the histidine decarboxylase activity and in the histamine concentration in all brain areas studied. In adult SHR, the development of hypertension was not influenced by -FMH. In young SHR, -FMH elicited a transient delay in the development of hypertension followed by a short-lasting tendency for increased blood pressure. It is concluded that histaminergic neurons of the brain play, if at all, only a secondary role in the development of hypertension in SHR.This work was supported by the Fonds zur Förderung der wissenschaftlichen Forschung.     

Modification of rat thermal responses to morphine by α-FMH suggests a role for neural histamine in morphine tolerance

In rats, morphine may either raise or lower body temperature depending on the dose. A morphine dose of 50 mg/kg, i.p., consistently produced a nearly maximal hypothermic response in non tolerant rats, whereas this dosage induced an elevation of body temperature in tolerant rats. In rats pretreated with -fluoromethylhistidine (-FMH), an irreversible inhibitor of histidine decarboxylase which induces a reduction in brain histamine synthesis, this morphine dose of 50 mg/kg, i.p. produced an elevation of rectal temperature resembling that observed in morphine-tolerant rats. To confirm the suggestion that hyperthermic effects of the higher dose of morphine in morphine-tolerant rats or in -FMH-preteated rats could be related to a possible involvement of mediators of fever, e.g. prostaglandins, animals were pretreated with acetylsalicylic acid (aspirin, Bayer) 30 mg/kg, i.p., 60 min before morphine. Results showed that acetylsalicylic acid prevented the hyperthermic response of morphine, resulting in a fall in body temperature. Since morphine releases histamine and -FMH inhibits histamine synthesis, our data demonstrating that an inhibitor of prostaglandin-synthetase showed efficacy only in animals responding with fever to the higher dose of the opiate, suggests a physiological antagonism between histamine and prostaglandins on mechanisms underlying hyper/hypothermic responses to morphine.     

Involvement of brain histamine in basal and stress-induced release of prolactin in the rat

We investigated whether inhibition of brain histamine (HA) synthesis by -fluoromethylhistidine (-FMH) can influence basal or stimulated prolactin (PRL) release in male rats. -FMH was administered either into the carotid (i.a., 20 and 100 mg/kg) or intracerebroventriculary (i.c.v., 200 g/rat) into freely moving rats with indwelling catheters. Plasma PRL levels were measured 90, 120, 180 min later. Both i.a. and i.c.v. administration of -FMH significantly inhibited basal PRL secretion at 120 and 180 min. When PRL secretion was stimulated by exposing rats to restraint stress, -FMH administered 3 h before the stress (20 and 100 mg/kg, i.a.; 200 g/rat, i.c.v.) was able to prevent the PRL surges at 10 and 20 min after stress. These results suggest that endogenous brain HA has a facilitatory role in the control of PRL secretion in rats.     

A selective role for brain histamine in prolactin release induced by opiates

We studied the effects of histamine (HA) antagonists on the facilitatory action of morphine (M) and-endorphin (E) on prolactin (PRL) release and the effect of -fluoromethylhistidine (-FMH, inhibitor of HA synthesis) onE-induced PRL secretion. Male rats were injected intracerebroventricularly (i.c.v.) with mepyramine (MEP, H₁-antagonist, 0.8 mol/rat) or ranitidine (RAN, H₂-antagonist, 0.4 mol/rat) 10 min before M (6 mg/kg, intracarotid, i.a.) orE (0.25 g/rat, i.c.v.). -FMH (200 g/rat, i.c.v.) was administered 3 h beforeE. Plasma PRL levels were measured at various times before and after drug treatment. RAN but not MEP significantly reduced PRL release induced by M whereas neither HA-antagonists nor -FMH modifiedE-induced PRL release. The results obtained show that brain HA contributes through activation of H₂-receptors to the PRL facilitatory action of M but not ofE.     

The role ofγδ T cells in the normal and disordered immune system

Summary A small population of T cells does not express the conventional T cell receptor characterized by the and polypeptide chains (TCR) but instead, two polypeptides termed and (TCR). This alternative receptor is able to recognize antigen. It appears early in T cell ontogeny, but its role in the thymus prior to the availability of TCR remains unclear. In selected sites such as skin or gut TCR predominates in mice which might suggest a role of T cells in the first line of defense against infection, T cells secrete lymphokines and display cytotoxic activity. However, their activation requirements may differ from what is known for T cells since MHC-nonrestricted and also CD4 and CD8 negative T cells have been described. Preferential activation by mycobacterial antigens possibly indicates a special repertoire of the T cells. In various diseases slightly increased numbers of T cells were found, but these preliminary studies have not yet provided evidence for a major pathogenetic role of T cells.List of abbreviations C constant region (immunoglobulin or TCR gene segment) - CD4 cluster of differentiation 4 (mainly on helper cells) - CD8 cluster of differentiation 8 (mainly on cytotoxic cells) - D diversity region (immunoglobulin or TCR gene segment) - DNA desoxyribonucleic acid - IL2 interleukin 2 - J joining region (immunoglobulin or TCR gene segment) - kD kiloDalton - MHC major histocompatibility complex - NK natural killer (cells) - RA rheumatoid arthritis - TCR T cell receptor - V variable region (immunoglobulin or TCR gene segment)     

Studien über den Mechanismus der Immunhämolyse: Der Bindungsmodus der vierten Komplementkomponente

Zusammenfassung Die Bindung der vierten Komplementkomponente (C₄) an sensibilisierte Hammelblutzellen (EA) ist von der vorhergehenden Bindung der ersten Komplementkomponente abhängig. Das Präparat EAC₁ kann, wenn ihm C₄ in geeigneter Form angeboten wird, in den Komplex EAC_1,4 überführt werden. Hierbei verschwindet der titrierbare Gehalt der flüssigen Phase an C₄; gleichzeitig acquirieren die Zellen die Fähigkeit, mit R₄ zu lysieren. Der zeitliche Ablauf dieser Veränderung wird untersucht. Die Eeaktion zwischen EAC₁ und C₄ verläuft äußerst schnell, und ihre Geschwindigkeit wird durch die Reaktionstemperatur nicht beeinflußt. Während die Bindung von C₁ an EA nur in Gegenwart von Ca⁺⁺ erfolgt, läuft die Bindung von C₄ an EAC₄ auch in Abwesenheit von zweiwertigen Metallionen ab. Die vonLevine u.Mayer als ein Ganzes betrachtete Ca⁺⁺-abhängige Überführung von EA in EAC_1,4 besteht mithin aus zwei aufeinanderfolgenden Teilreaktionen, von denen die erste (C₁-Bindung) calciumabhängig und die zweite (C₄-Bindung) von zweiwertigen Ionen unabhängig ist.Mit Unterstützung der Deutschen Forschungsgemeinschaft sowie der Gesellschaft der Freunde und Förderer der Medizinischen Akademie Düsseldorf.     

Biophysical studies of teschen disease virus (Talfan strain)

Summary Studies have been made of the heterogeneity of infectivity and CFA in Teschen virus (Talfan strain) suspensions. Most of the infectivity was contained in two components of densities 1.46 gm./ml. and 1.35 gm./ml. The physical, chemical and immunological properties of these components have been compared. It was possible, however, to convert a large proportion of 1.46 component to 1.35 component by treating the 1.46 component with sodium dodecyl sulphate. This would indicate that the 1.46 component was a complex formed between the infective particles and cellular debris.Further studies on the growth characteristics and electron microscopy of the virus have been made.     

Gravity responses of Purkinje cells in the nodulus

Summary In cats, either decerebrated or under chloralose anaesthesia, Purkinje cells (P-cells) of the cerebellar nodulus have been examined with the animal under static lateral tilt (roll±20°). The cell activity was extracellularly recorded and both simple and complex spike discharge patterns were studied.In 20 cells out of a population of 198, simple spike firing was found to be affected by static roll. Ten cells had an -type response, 8 a -type, while only single examples of and activations were found.Out of 67 Purkinje cells tested for complex spike activation, 5 were found to be sensitive to static roll, 4 with an or response and one with a response.The results are to be attributed to pure otolith activation and show that this input is able to modulate P-cell activity in the nodulus through both the mossy fibre and the climbing fibre systems.     

Neuronal nicotinic acetylcholine receptors expressed in Xenopus oocytes: role of the α subunit in agonist sensitivity and desensitization

Neuronal nicotinic acetylcholine receptors (nAChRs) were expressed in Xenopus laevis oocytes after nuclear injection of complementary deoxyribonucleic acid (cDNA) expression vectors. The two receptor subtypes 4/n1 and 3/n1 were readily distinguishable from one another by ACh sensitivity and desensitization. 3/n1 receptors showed lower ACh sensitivity and stronger desensitization than 4/n1 receptors. Furthermore, although the current/voltage relationship was very similar in both receptor subtypes, the voltage dependence of desensitization was found to be strikingly different. As the n1 subunit was unchanged, the subunits must be responsible for these functional differences. Symmetric hybrid cDNAs, 43 and 34, were constructed and functional receptors were obtained by co-injection with n1. These hybrid receptors displayed an ACh sensitivity that was mainly defined by the extracellular sequence of the subunit. In contrast, no part of the subunit was found fully to determine desensitization.     

On the terms “reticulosis” and “reticulum cell sarcoma” with regard to the modern concept of the monocyte macrophage system

Summary The terms reticulosis and reticulum cell sarcoma (= malignant lymphoma, histiocytic type) are discussed regarding the modern concept of the monocyte macrophage system which today has replaced the ancient theory of the reticuloendothelial system. The monocyte macrophage system is not independent, but closely related to the myeloid system. Thus, a third blood forming system as was believed in the case of RES does not exist. Phagocytic reticulum cells of the various hematopoietic organs are highly activated monocyte-derived macrophages. All those conditions formerly termed reticuloses have been found to belong either to the myeloid or to the lymphatic system. Considering the reticulum cell sarcomas or malignant histiocytic lymphomas, most of them seem to be of lymphatic rather than of macrophage origin, representing highgrade malignant lymphomas, possibly immunoblastic sarcomas. No relationship between these tumours and the monocyte macrophage system has been established, so far. Therefore, the terms reticulosis and reticulum cell sarcoma should be no longer used in order to avoid confusion, in order to stimulate sufficient diagnostic efforts which will really clarify such cases, and in order to give full credit to modern results of hematopathology.     

Analysis of γδ+ T cells in peripheral blood of children with perinatal human immunodeficiency virus (HIV) infection

The present study examined CD8 antigen expression and variable (V) gene segment usage by T cell receptor (TCR)-⁺ lymphocytes in peripheral blood of symptomatic children with perinatal HIV infection. The relative number of ⁺, CD8⁺ T cells in most of the infected children was higher than that in uninfected children from HIV⁺ or HIV^– mothers and correlated with the immunodeficiency status of the patients. Infected infants and children over 1 year old also showed an increased proportion of V1-J1⁺ T lymphocytes. CD8 expression on those cells was higher in infected than in uninfected infants and children. Sequence analysis of the gene rearrangement of the predominant V1 family in peripheral blood of three HIV⁺ donors revealed extensive junctional diversity. These results suggest that the V skewing in the majority of HIV⁺ children reflects peripheral expansion of V1-J1⁺ T lymphocytes early in life, which might be involved in the mechanisms of HIV-induced immunodeficiency.     

Oligogenic determination of morphine analgesic magnitude: A genetic analysis of selectively bred mouse lines

Two ongoing selective breeding projects have produced mice that display divergent analgesic responses to morphine. These two projects have selected for similar phenotypes: high and low levorphanol analgesia (HAR/LAR lines; Portland, OR) and high and low swim stress-induced analgesia (HA/LA lines; Jastrzebiec, Poland). Evidence suggests genetic commonalities between mice of the two projects. Using a Mendelian breeding protocol, we have recently found that one or two genetic loci predominantly determine the high morphine analgesia exhibited by HA mice. In the present study we demonstrate that the differential morphine analgesia (5 mg/kg. i.p.) displayed by HAR and LAR mice is similarly oligogenic, predominantly determined by two unlinked loci. A complementation analysis, in which the analgesic responses to morphine of the recessive homozygotes of each project (HAR and HA) were compared to those of their hybrid offspring (HAR x HA), revealed that different genetic loci have been fixed in each project. An intriguing bimodal distribution was observed in the HAR x HA population: Some HAR x HA hybrids displayed greater morphine analgesia than either HAR or HA mice, whereas others displayed minimal analgesia. LAR x LA hybrids displayed less analgesia than either LAR or LA mice. The analgesic responses of HAR x LA and LAR x HA mice were comparable to those of their low-line parents. These findings indicate not only that different loci were responsible for producing high morphine responders in each selection project but that these distinct loci can interact synergistically to produce superhigh and superlow responders.     

On the regulation of the expressed L-type calcium channel by cAMP-dependent phosphorylation

The Ca²⁺ channel subunits _1C-a and _1C-b were stably expressed in Chinese hamster ovary (CHO) and human embryonic kidney (HEK) 293 cells. The peak Ba²⁺ current (I _Ba) of these cells was not affected significantly by internal dialysis with 0.1 mM cAMP-dependent protein kinase inhibitor peptide (mPKI), 25 M cAMP-dependent protein kinase catalytic subunit (PKA), or a combination of 25 M PKA and 1 M okadaic acid. The activity of the _1C-b channel subunit expressed stably in HEK 293 cells was depressed by 1 M H 89 and was not increased by superfusion with 5 M forskolin plus 20 M isobutylmethylxanthine (IBMX). The _1C-a·₂·₂/ complex was transiently expressed in HEK 293 cells; it was inhibited by internal dialysis of the cells with 1 M H 89, but was not affected by internal dialysis with mPKI, PKA or microcystin. Internal dialysis of cells expressing the _1C-a·₂·₂/ channel with 10 M PKA did not induce facilitation after a 150-ms prepulse to +50 mV. The Ca²⁺ current (I _Ca) of cardiac myocytes increased threefold during internal dialysis with 5 M PKA or 25 M microcystin and during external superfusion with 0.1 M isoproterenol or 5 M forskolin plus 50 M IBMX. These results indicate that the L-type Ca²⁺ channel expressed is not modulated by cAMP-dependent phosphorylation to the same extent as in native cardiac myocytes.     

Biochemical studies on histaminergic systems in mammalian brains

The effects of (±)-fluoromethylhistidine (-FMH), a new histidine decarboxylase (HD) inhibitor, were investigated in vitro and in vivo. Following a preincubation with (±)-FMH, brain HD-activity was progressively inhibited and could not be restored by dialysis, thus indicating the irreversible nature of this inhibition, Moreover, in vivo, a single intraperitoneal dose of 20 mg/kg of (±)-FMH induced a complete and rapid loss of HD activity in gastric and brain tissues. The time-course of recovery was different according to the tissue studied. At a dose of 100mg/kg (±)-FMH did not modify histamine-N-methyl transferase (HMT), DOPA decarboxylase and glutamate decarboxylase activities.A high affinity binding of³H-histamine was seen in particulate fractions from rat brains. The regional and subcellular distributions of these binding sites indicate that they are not related to HMT. They are likely to represent post-synaptic HA-receptors in view of their decrease after kainate-induced degeneration of neuronal perikarya in the striatum and their increase following interruption of the histaminergic inputs which suggested a denervation hypersensitivity. However, their pharmacological specificity was distinct from either H₁-or H₂-receptors, and the possibility of a modified conformational state of HA-receptors was raised by the selective effect of guanylnucleotides.     

Haemoglobin in trematodes 1. Fasciola gigantica. 2. Cotylophoron indicum

Summary 1. Haemoglobin content of two trematodes, Fasciola gigantica collected from the bile ducts and Cotylophoron indicum from the reticulum of buffaloes has been investigated spectroscopically and by alkaline haematin method.2. The host's blood haemolglobin has been examined spectroscopically.3. Oxy- and Carboxyhaemoglobin absorption bands of the two parasites differ amongst themselves as also from that of the host.4. It is concluded that haemoglobin of the parasites differs from blood haemoglobin of the buffalo — their host — in (i) the position of absorption bands and (ii) the span.5. The tissue haemoglobin of the parasites is haemoglobin and not myoglobin.     

Activated charcoal is as effective as fuller's earth or bentonite in paraquat poisoning

Summary In vitro investigations have shown that the adsorption capacity of activated charcoal (Kohle-Compretten, Ultracarbon, E. Merck, Darmstadt, FRG) is just as high as that of Fuller's earth (Surrey powder, Laporte Industries Ltd., Luton, GB) or Bentonite BP W.B. (Steetley Minerals Ltd., Milton Keynes, GB). Fuller's earth (Fullererde) from another manufacturer has had very poor adsorption properties and is thus not suitable for the treatment of paraquat poisoning. Animal experiments have shown that the curative effect of activated charcoal given 0.5, 1, 2, and 3 h after ingestion of 200 and 300 mg paraquat/kg body weight is equally as good or even better than that of Fuller's earth or Bentonite BP W.B.. Activated charcoal is a substitute of equal value to these mineral soils.     

Das herzmuskeleigene Acetylcholin

Zusammenfassung Mit der in einer vorangegangenen Mitteilung angegebenen Methodik wurde der Gesamtgehalt der Herzmuskulatur an gebundenem Acetylcholin in /g Frischgewicht (ausgedrückt in Acetylcholinchloridäquivalenten) bestimmt.An 141 Froschherzen und 59 Rattenherzen fanden sich folgende Werte:Die Vorhofsmuskulatur von Rana temporaria enthält im Herbst 0,45 (± 0,158), im Frühwinter 1,40 (± 0,58) /g. Die Kammermuskulatur der gleichen Art enthält für Frühjahr, Sommer und Herbst im Mittel 0,34 (± 0,10) /g, ab Oktober steigen die Werte, wir fanden von Oktober bis Dezember 0,59 (± 0,25) /g. Die Werte von Herzbasis und Herzspitze von Rana temporaria zeigen eine große Streuung und keine signifikanten Unterschiede. Die Ventrikelmuskulatur von R. esculenta ergab im Durchschnitt von 30 Versuchen (Juli—Oktober) 0,62 (± 0,29) /g. Die Oktoberwerte sind gegenüber den Sommer- und Herbstwerten etwas erhöht. Im Gesamtdurchschnitt hat die Herzkammer von R. esculenta etwas mehr ACh als diejenige von R. temporaria.Die Vorhofsmuskulatur der Ratte zeigt mit 2,28 (± 0,547) /g Frischgewicht einen recht hohen ACh-Gehalt. Der Rattenventrikel besitzt rechts mehr ACh als links, der Wert der Muskulatur des rechten Ventrikels beträgt 1,30 (± 0,22) /g, derjenige des linken Ventrikels 0,73 (± 0,148) /g.     

An analysis of postsynaptic potentials of tectal neurons of the frog: correlation with impulses recorded from the terminals of retinotectal afferents

Summary The purpose of this study is to examine the synaptic action between terminals of retinal ganglion cell axons and tectal neurons. To accomplish this, an extracellular single unit identified as retinotectal fiber was first isolated from the superficial layer of the optic tectum and intracellular responses were recorded from a tectal neuron in the vicinity of the extracellular recording electrode. On-off retinal fibers and both E-E (EPSP at on and off of diffuse light) and EI-EI type (EPSP-IPSP combination at on and off of diffuse light) tectal neurons were selected for the pre- and postsynaptic pair. Postsynaptic responses to a small moving square were averaged by triggering with the isolated presynaptic impulses. The latency of the resultant EPSPs indicated that most of the E-E and EI-EI type tectal neurons were monosynaptically activated by on-off retinal fibers. One of the E-E type tectal neurons was identified as a large ganglionic neuron in layer 8.