Transmitter metabolizing enzymes and free amino acid levels in sensory and motor nerves and ganglia of the shore crab (Carcinus maenas)

Regional distribution of putative amino acid neurotransmitters in the CNS of spiders (Arachnida: Araneida)

The regional occurrence of five amino acid neurotransmitters (GABA, taurine, glycine, glutamate, aspartate) was studied in the CNS of five spider families, using a fluorescence microchromatogram method. Clear differences in transmitter distribution were obvious in relation to the phylogenetic standard of the spider families and the CNS regions investigated. For example, high relative amounts of taurine and GABA were typically confined to the protocerebral brain parts, particularly in the Araneidae and Salticidae. Remarkable amounts of glutamate were shown to exist in the lower CNS parts of the Agelenidae and, especially, the Theraphosidae. The results obtained confirm the dominant functional role of the protocerebrum in arthropods.

The effects of acetylcholine, carbamylcholine and gamma-aminobutyric acid on uropod motoneurons in the crayfish Procambarus clarkii and Cambaroides japonicus

The effects of acetylcholine (ACh), carbamylcholine and gamma-aminobutyric acid (GABA) on the spike activity of uropod motoneurons were investigated electrophysiologically in the crayfish Procambarus clarkii Girard and Cambaroides japonicus de Haan. High concentrations of ACh were required to bring about an increase in the spike discharge of uropod motoneurons while carbamylcholine, which is not destroyed by cholinesterase, caused a marked increase in the motoneuron spike discharge even in low concentrations. Application of GABA in concentrations of 10(-5)-10(-2) M caused the decrease in the spike discharge of uropod motoneurons. Under the condition that the synaptic transmission onto uropod motoneurons was blocked by perfusing EGTA containing Ca2+-free saline with high-Mg2+, ACh increased the spike discharge of uropod motoneurons whereas GABA decreased it. The results suggested that ACh and GABA function as excitatory and inhibitory transmitters, respectively, in the crayfish central nervous system.

Platelet MAO, personality and response to lithium prophylaxis

Patients with bipolar affective disorder and who were maintained on long lithium prophylaxis were evaluated retrospectively regarding response to lithium. Good responders to lithium prophylaxis were compared to non-responders and to normal controls on platelet MAO activity, and on psychological variables (Eysenck's extraversion, neuroticism, psychoticism and lie scale; Foulds' extrapunitiveness, intropunitiveness and dominance). Lithium responders, non-responders and normal controls had similar platelet MAO activity. There was a tendency for higher plasma lithium levels to be associated with higher platelet MAO activity in male patients but not in females. Lithium non-responders exhibited significant correlations between their platelet MAO activity and their test scores on psychoticism, and extraversion. Lithium non-responders, compared to responders and normals, showed abnormal personality profiles on neuroticism, and dominance.

Fine structural localisation of acetylcholinesterase activity in the compound eye of the honeybee (Apis mellifica L.)

Acetylcholinesterase (AChE) activity was demonstrated histochemically at the electron microscopic level in the compound eye of the worker bee (Apis mellifica L.) by use of the method of Lewis and Shute (1969). All photoreceptor axons (short and long visual fibres) display AChE activity. The reaction product is located in the axoplasm and at the plasma membrane. Substantial amounts of the reaction product can be detected in the intercellular spaces between the visual fibres. Along the visual fibres, the enzyme activity is unevenly distributed. High AChE activity is present in the distal parts of te axons, in contrast to lower enzyme levels in the lamina. However, AChE is also present in the proximal terminals of the visual fibres as well as in the intercellular spaces between visual fibre terminals and the postsynaptic neurones (monopolar cells). Intracellular enzyme activity is almost absent in the monopolars. The authors assume the high AChE activity in the visual fibres to be indicative of acetylcholine as the transmitter at the first synapse of the compound eye. This hypothesis is discussed in view of the results of autoradiographic, electrophysiological and pharmacological investigations of the compound eye and of hte ocellus. Our data are a variance with results of studies on the eyes of Diptera.

Acetylator status and inhibition of platelet monoamine oxidase following treatment with phenelzine

The activity of platelet monoamine oxidase(MAO)was measured in 22 severely depressed patients before and after treatment with 45 mg and 60 mg phenelzine. The per cent inhibition of platelet MAO after both doses was not related to acetylator status.

Phenelzine, since it is a hydrazine derivative, is probably metabolized by polymorphic acetylation. Patients who were phenotypically slow acetylators have been reported to show a better clinical response (Johnstone & Marsh, 1973) and more side-effects (Evanset al.1965) to a given dose of phenelzine than patients who were fast acetylators.

Isolation of organic anions by extraction with liquid anion exchangers and its application to micromethods for acetylcholinesterase and 4-aminobutyrate aminotransferase

Organic anions of particular importance to biochemistry such as Krebs cycle intermediates, glycolysis intermediates, simple fatty acids, adenine nucleotides and CoA derivatives can be quantitatively extracted from a buffered solution by high-molecular-weight ammonium salts in an organic solvent. Phosphate salts of tertiary amines in chloroform were the most efficient extractants. The isolation procedure was found to be an example of amine neutralization. The effect of pH, different inorganic anions, volume ratios between the two phases, concentration of the isolated anions and concentration of the ammonium salts have been investigated. The extraction technique has been applied to rapid and sensitive radiochemical methods for the determination of acetylcholinesterase and 4-aminobutyrate aminotransferase activities.