Dopamine and octopamine in whole body extracts of the bulb mite

Summary Using high performance liquid chromatography with electrochemical detection, whole body extracts of the bulb mite,Rhizoglyphus echinopus (Fumouze and Robin), were found to contain the biogenic amines dopamine and octopamine at concentrations of 4.3±0.6 and 2.3±1.4 ng g^–1 wet weight, respectively. Adrenaline, noradrenaline, tyramine,N-methyldopamine,N-acetyldopamine, and 5-hydroxytryptamine, if present, were below the limits of detectability. This is the initial demonstration of the presence of octopamine in a mite species.     

Immunocytochemical localization of GnRH (gonadotropin releasing hormone) systems in the brain of a marine teleost fish,the sole

Summary The GnRH system was studied in the brain of the sole by immunocytochemistry (peroxidase-antiperoxidase method) (PAP) using antibodies to synthetic salmon GnRH (s-GnRH). Two centers containing immunoreactive cell bodies were observed in the forebrain, one located at the junction between the olfactory bulbs and the telencephalon and the other in the preoptic area. Numerous immunoreactive fibers were found, especially in the telencephalon, hypothalamus, pituitary, optic tectum and retina.     

Illusory shifts in visual direction accompany adaptation of saccadic eye movements.

A central problem in human vision is to explain how the visual world remains stable despite the continual displacements of the retinal image produced by rapid saccadic movements of the eyes. Perceived stability has been attributed to 'efferent-copy' signals, representing the saccadic motor commands, that cancel the effects of saccade-related retinal displacements. Here we show, by means of a perceptual illusion, that traditional cancellation theories cannot explain stability. The perceptual illusion was produced by first inducing adaptive changes in saccadic gain (ratio of saccade size to target eccentricity). Following adaptation, subjects experienced an illusory mislocalization in which widely separated targets flashed before and after saccades appeared to be in the same place. The illusion shows that the perceptual system did not take the adaptive changes into account. Perceptual localization is based on signals representing the size of the initially-intended saccade, not the size of the saccade that is ultimately executed. Signals representing intended saccades initiate a visual comparison process used to maintain perceptual stability across saccades and to generate the oculomotor error signals that ensure saccadic accuracy.     

A specific protein in the genusRhynchosciara (Diptera,Sciaridae)

Summary Proteins immunologically related toRhynchosciara americana larval protein 10 occur in the hemolymph and ovaries of five different fly species of the genusRhynchosciara. Electrophoretic analyses showed these proteins to have a mol.wt similar to that of theR. americana protein 10 (43,000), e.g. theR. hollanderi protein 44,300, theR. milleri protein 45,500.     

Studies on correlations between chloroquine-induced tissue damage and serum enzyme changes in the rat

The administration of chloroquine to rats resulted in a significant elevation of serum enzymes and a corresponding decrease of these enzymes in the tissues. The changes in serum and kidney enzymes were most marked, thus indicating a primary renal dysfunction.     

Bicuculline and picrotoxin block gamma-aminobutyric acid-gated Cl- conductance by different mechanisms

Using isolated, internally perfused bullfrog dorsal root ganglion cells we have studied the dose-response curves for gamma-aminobutyric acid (GABA) in the presence of internally or externally applied GABA antagonists. With external application of antagonists the inhibition of the GABA current by bicuculline was competitive and that by picrotoxin was noncompetitive. Picrotoxin but not bicuculline blocked when internally perfused.     

Normetanephrine and metanephrine oxidized by both types of monoamine oxidase

Summary Both normetanephrine and metanephrine were found to be oxidized by both types of monoamine oxidase in mouse liver mitochondria. Both K_m and V_max values of type B MAO for both substrates were higher than those of type A MAO, which caused the shift of inhibition curves with clorgyline and deprenyl according to the increase in substrate concentration.     

Role of calcium in the histamine release induced by D-galactosamine from rat mast cells

Rat peritoneal mast cells were isolated and purified by differential centrifugation in Ficoll. Cells pooled from three to four rats were suspended at approximately 10(6) cells/ml in a buffered salt solution and incubated for 1 h at 37 degrees C in 300 microliter volumes in the absence or presence (9 X 10(-4) M) of calcium chloride. Addition of D-galactosamine hydrochloride (DGM; 2.8 X 10(-4)M) caused (in addition to basal release) a mean +/- SEM percent histamine release of 15.7 +/- 5.2 in the presence of Ca++ and 19 +/- 4.9 in the absence of Ca++ (p greater than 0.05). It is suggested that D-galactosamine does not require extracellular Ca++ for the release of histamine from the rat mast cell.