Metrifonate effects on acetylcholine and biogenic amines in rat cortex

The effect of systemic and local administration of metrifonate (MTF), a long-acting cholinesterase inhibitor (ChEl) on extracellular levels of acetylcholine (ACh), norepinephrine (NE), dopamine (DA) and serotonin (5-HT) was investigated in the rat cortex by using transcortical microdialysis. Metrifonate (20, 40, and 80 mg/kg, s.c.) increased ACh levels in a dose-dependent manner above the baseline. Two consecutive administrations (80 mg/kg) enhanced ACh levels producing two similar patterns of elevation. A significant increase in NE was also seen at 80 mg/kg. Systemic administration (20 mg/kg) of MTF produced a significant increase of DA levels. Local cortical perfusion of MTF through the probe caused a significant but slow increase of ACh as well as an increase of NE levels. Compared to NE, the elevation of DA was more rapid and more longlasting. The cortical levels of 5-HT were not modified by MTF given by either route. These results support the concept of MTF being a potential drug for treatment of Alzheimer disease (AD).     

On the haemodynamic effects of biogenic amines in isolated fish gills

The effects of histidine and histamine on branchial vascular haemodynamics were studied using the isolated, perfused gill of the tropical cichlid, Oreochromis (Sarotherodon) niloticus. Histidine had no vasoactive effect while histamine induced vasodilatation. Histamine-induced vasodilatation was irreversibly inhibited by the H1 and H2 receptor antagonists, piriton and cimetidine, respectively. This suggests a possible involvement of the non-neurogenic histaminergic system, acting directly via H1 and H2 histamine receptors, in the regulation of branchial vascular haemodynamics in teleosts.     

Distribution of biogenic amines in rat brain with hypothermia

Distribution of catecholamines and serotonin in the thalamus and hypothalamus of the brain was studied as affected by hypothermia. Both single and double hypothermia are found to induce considerable shifts in distribution of these amines. In the both regions of the brain the content of serotonin increases greatly, that of dopamine and adrenaline rises to a less extent. The amount of norepinephrine as compared to the control in unchanged.     

Histochemical reaction to biogenic amines of the nervous system of the larval and mature cestode Microsomacanthus microskrjabini

Histochemical reaction with glyoxylic acid has revealed a specific fluorescence caused by the presence of indolamine (apparently serotonin) in the nervous system of larva and mature cestode. Fluorescence manifests itself in neurons and nerve fibres of the central ganglion and its commissure, in nerve cells of the proboscis, in longitudinal trunks and transverse commissures, and in the nerve elements connected with genital system.     

Scanning electron microscopic evaluation of effects of low pH on gills of Channa punctata (Bloch)

Bioassay of Channa punctata (± 36 g) was carried out in acidic waters of different pH. A 96 h LC₅₀, value was obtained at pH 5.3. Scanning electron microscopy of gills of C. punctata showed fusion of adjacent secondary lamellae. At this low pH, dissociation of epithelium of branchial arches and gill filaments take place. At 360 h the branchial epithelium ruptures developing lesions in the gills exposing the efferent filament vessels. At pH 6.6 the tips of adjacent filaments belonging to both oral and aboral hemibranchs fuse in blocks.     

Studies on the reaction of fluorescamine with primary amines

Fluorescamine is a useful reagent for the fluorometric assay of primary amines. The extent of the reaction between fluorescamine and primary amines, as well as the fluorescence intensities of the resulting fluorophors depend on pH, solvent composition and reagent concentration. Optimum values for these variables further depend on the amine under study. The influence of these parameters on the fluorogenic reaction of representative amines, and on their fluorophoric derivatives has been investigated, and the results are reported here.     

The effects of using lactic acid bacteria inoculants in maize silage on the formation of biogenic amines

Silages from five ripened varieties of silage maize with dry matter contents ranging between 275 and 410 g/kg were prepared in five laboratory experiments. Whole-plant maize was fermented at 22°C and silages were then stored at the same temperature for 4 months. Spontaneously fermented silages were prepared as control variants and compared with silages inoculated with commercial strains of Lactobacillus plantarum, Lactobacillus buchneri and a mixed preparation Microsil containing L. plantarum, Lactobacillus casei, Enterococcus faecium and Pediococcus pentosaceus. The starter cultures were applied at doses 5·10⁵ and 5·10⁶ CFU/g of chopped maize. Seven biogenic amines and polyamines were extracted from silages with perchloric acid and determined as N-benzamides by micellar electrokinetic capillary chromatography. Common chemical criteria of silage quality were also determined. All three inoculants, mainly at the higher dose, decreased significantly contents of tyramine, putrescine and cadaverine, three undesirable amines occurring at the highest levels. L. plantarum was the most effective. Contents of histamine and tryptamine were low in all experimental silages. Also relatively low were levels of polyamines spermidine and mainly of spermine.     

Effect of biogenic amines and cannabinoids on bacterial chemotaxis

The chemotactic response of Pseudomonas fluorescens was significantly enhanced by the stimulants dl-amphetamine and epinephrine. Acetylcholine, a physiological antagonist of epinephrine, and the cannabinoid tetrahydrocannabinol inhibited bacterial chemotaxis. It may be possible to use bacterial chemotaxis as a bioassay in biochemical studies of drug action.     

Effect of biogenic amines on phagocytosis in Tetrahymena thermophila

Stimulation of phagocytosis by serotonin and catecholamines in Tetrahymena grown in proteose-peptone medium proved to be concentration dependent, the optimal concentrations being approximately 0.1 to 1.0 microM. The serotonergic antagonists, spiperone, and metergoline, also stimulated the process, whereas the beta- and alpha-adrenergic antagonists, propranolol, alprenolol, and ergocryptine, had no effect or inhibited phagocytosis. A wide variety of derivatives of the biogenic amines had no effect on phagocytosis, demonstrating the specificity of recognition mechanism for neurohormones in Tetrahymena. Such hormones act by at least two independent mechanisms, one for adrenergic agonists, another for dopamine. Presumably, recognition mechanisms for hormones in protozoa resemble in some respects those in multicellular organisms, therefore bespeaking a common origin.     

The effects of biogenic amines on conditioned and unconditioned responses to olfactory stimuli in the honeybeeApis mellifera

Summary Photo-orientation of the pond snailLymnaea stagnalis (Gastropoda, Pulmonata, Basommatophora) was tested in a directed light field. The snails were tested, one at a time, on a horizontal glass plate in a frosted black perspex tank (Fig. 1). Intact control snails showed a clear positive photo-orientation and removal of eyes, of tentacles, or of eyes and tentacles had only minor effects upon the orientation parameters tested (Fig. 2). Evidently non-ocular photoreceptors function in positive photo-orientation (Figs. 3, 4).One clear difference between the eyes and the non-ocular receptors could be demonstrated: after dark-adaptation intact animals orient very well at low light intensity, whereas blinded animals fail to do so (Fig. 5).The dermal light-on sensitive system is postulated to be responsible for the non-ocular orientation behaviour.     

Interference of biogenic amines with the measurement of proteins using bicinchoninic acid

The use of bicinchoninic acid (BCA) to measure protein concentrations has received wide acceptance because the reagent is insensitive to many of the buffers, sucrose solutions and detergents used with various tissue and enzyme preparations. However, any compound capable of reducing Cu2+ in an alkaline medium such as biogenic amines will produce a color reaction. The primary objective of this study was to determine whether biogenic amines present in neuronal tissue would interfere with the measurement of protein using the BCA method. Catecholamines were found to produce a linear increase in color of the BCA reagent at concentrations between 1 and 100 nmol/2.1 ml assay volume. Catecholamines appeared to be more sensitive to the BCA reagent than either serotonin or ascorbic acid. Catecholamines at concentrations of 50 nmol/mg of protein or 1 nmol/2.1 ml assay volume or higher will produce significantly (P less than 0.0001) higher color reactions than protein alone. The BCA reagent is not ideal for measuring protein concentrations of intact synaptic vesicles and chromaffin granules since the catecholamine concentrations in these organelles are high enough to increase the color developed by 1.1 to 2.5 times that observed with protein alone. The linearity of the color development produced by catecholamines suggest that BCA could be used to quantitate catecholamine concentrations between 1 and 100 nmol. The BCA reagent will not distinguish between the different catecholamines.