Effect of GABA-ergic substances on the analgesic effect of morphine in rats]

The effect of GABA-ergic compounds on morphine-induced analgesia was studied to reveal probable interaction of GABA and opiates. As an index for morphine effect the reaction of vocalization in response to electrical stimulation of the rat tail was used. It was shown that thiosemicarbazide, the inhibitor of glutamate decarboxylase and bicuculline, GABA-ergic receptor blocking agent, which were proposed to be joined in a group of GABA-negative compounds, reduce and shorten the effect of morphine. Depakine, the inhibitor of alpha-ketoglutarate-GABA-transaminase, as well as GABA itself administered in high doses (GABA-positive actions) make morphine analgesia more pronounced and longer. Probable causes of the described interrelationship between GABA and opiates are discussed.     

Mental health in situations of armed conflict

Mental health is a serious problem in Latin America where many communities have been directly affected by armed conflict, communities in which large population groups have been displaced or have sought refuge. Research studies and epidemiological statistics are summarized to emphasize the psychosocial consequences of traumatic events associated with armed conflict. In addition to specific psychological disorders, other more generalized are considered such as fear, affliction, diseases, social disorder, violence and psychoactive substance consumption. Finally, the main points of a mental health plan for emergency situations are described which include the following: (1) preliminary diagnosis, (2) increase, decentralize and strengthen mental health public services, (3) psychosocial attention to the prevailing disorders--with emphasis on childhood problems, (4) initiate training and use of non-specialized personnel, and (5) identification of special needs requiring attention by psychologists and psychiatrists. Other aspects emphasized were community education, training, social communication, community organization, social participation, interinstitutional coordination, flexibility, sustainability, and specific actions in accordance with local needs.     

Effect of serotoninergic substances on escape behavior in acute stress situations

The data are provided on the effect of some serotoninergic substances on the avoidance behavior under acute stress. 5-Hydroxytryptophan, zimelidine (low doses), pyrenepyron, ciproheptadine, trazodon (high doses), produced a noticeable positive action on the behavior pattern under study. Quipazin and zimelidine (high doses) provoked an increase in the number of affective manifestations and a rise of the latent avoidance time. Regardless of an appreciable fall in the number of affective manifestations, the powerful sedative effect of m-chlorphenylpiperazine led to an increase in the latent response periods. It was shown that substances that produced a direct or mediated activation effect on the serotoninergic system had an appreciable favourable influence on the avoidance behavior, which was a consequence of a decrease in the animals' emotional excitement. Combination of serotonin-blocking properties (action on S2-autoreceptors) and dopaminergic properties brought about optimal results, provided that pyrenepyron was applied.     

Role of the GABA-ergic link in the development of the tranquilizing effect in cats

The development of the tranquilizing effect of n-dipropylacetate (n-DPA) selectively increasing the GABA level in the nerve terminals was studied in experiments on cats in comparison with diazepam effect. The changes in the spectrum of emotional-behavioral reactivity were estimated. In doses of 50 and 200 mg/kg n-DPA caused a marked antiphobic effect which was not accompanied by the activating component characteristic of diazepam. The n-DPA-induced increase in the GABA level in the nerve terminals is suggested to be important for the development of the anxiolytic effect of tranquilizers. The total increase in the GABA level in the nerve terminals is suggested to be important for the development of the anxiolytic effect of tranquilizers. The total increase in the GABA content in the brain correlates to a greater extent with the sedative effect of drugs.     

An unexpected effect of capsaicin on spontaneous GABA-ergic IPSCS in hippocampal cell cultures

Vanilloid receptors 1 (VRs1) expressed in a subpopulation of sensory neurons and responsible for processing of chemical and thermal noxious stimuli were also shown to be expressed in several cerebral structures and to be involved in the regulation of glutamatergic synaptic transmission. In this study, we started to investigate the possibility that VRs1 are also involved in the regulation of GABA-ergic synaptic transmission. For this purpose, the effect of a VR1 agonist, capsaicin, on spontaneous GABA-ergic inhibitory postsynaptic currents (IPSCs) was studied in hippocampal cell cultures using a patch-clamp technique. It was found that capsaicin (10 μM) decreased both the frequency and amplitude of spontaneous IPSCs. This finding suggests the involvement of VRs1 in the regulation of neuronal firing in some GABA-ergic interneurons and in the modulation of the efficacy of GABA-ergic synaptic transmission. However, considering the direction of the effect (a decrease in the IPSC frequency) and lack of its desensitization, the involvement of other receptor(s) also cannot currently be ruled out. Neirofiziologiya/Neurophysiology, Vol. 38, No. 4, pp. 364–367, July–August, 2006.     

Anxiolytic-like effect of neuropeptide Y (NPY), but not other peptides in an operant conflict test.

The peptide messengers neuropeptide Y (NPY), growth hormone-releasing hormone (GHRH), atrial natriuretic peptide (ANP) and beta-endorphin (BEND) were tested in an animal model of anxiety, the Geller-Seifter conflict test. Rats were subjected to a multiple schedule consisting of three components: in the first component, lever-pressing produced food-reward ('unpunished responding'). The second component was a time-out period, during which lever-pressing had no consequences. During the third component, lever-pressing produced food-reward, but was also punished by an incremental foot-shock ('punished responding'). After establishing a stable baseline of both unpunished and punished responding, animals were injected with various doses of NPY, GHRH, ANP, BEND, or with saline into the lateral cerebral ventricle, and testing was repeated. While changes in unpunished responding can reflect alterations in performance factors or motivational strength, increases in punished responding have previously been shown to be highly specific for anxiety-reducing drugs, such as the benzodiazepines. NPY markedly and dose-dependently increased punished responding. A smaller increase of unpunished responding was also seen. These results add further support to the hypothesis that NPY may be an endogenous anxiolytic. GHRH, ANP and END did not affect punished responding.     

Ultrasound and mating behaviour in rodents with some observations on other behavioural situations

Ultrasounds have been detected during mating behaviour in all 11 species of myomorph rodents in which this behaviour has been observed. The signals produced by each of the species studied are described. In all species except hamsters, these signals appear to be produced by the male. Ultrasounds have also been detected from rodents in other situations such as during and after disturbance and when placed in new surroundings. The possible significance of these ultrasonic signals in the lives of rodents is discussed.     

Occurrence of phytoalexins and other putative defense-related substances in uninfected parsley plants

Considerable amounts of the following substances were found in uninfected parsley (Petroselinum crispum) cotyledons: furanocoumarins, the putative phytoalexins of this and some related plant species, two enzymes of the furanocoumarin pathway (S-adenosyl-L-methionine: xanthotoxol and S-adenosyl-L-methionine: bergaptol O-methyltransferases), two hydrolytic enzymes (1,3--glucanase, EC 3.2.1.39, and chitinase, EC 3.2.1.14), and pathogenesis-related proteins. The furanocoumarins and the methyltransferase activities reached their highest levels at the onset of cotyledon senescence as the hydrolytic enzymes increased from low to relatively high activity values. The relative amounts of pathogenesis-related proteins 1 and 2, as well as the corresponding mRNAs, also increased markedly. Two enzymes of general phenylpropanoid metabolism, L-phenylalanine ammonia-lyase and 4-coumarate: CoA ligase, decreased in activity in a biphasic fashion during cotyledon development. At all developmental stages, the levels of these putative defense-related agents in total cotyledon extracts were too high to enable detection of, possibly, additional changes upon infection with zoospores of Phytophthora megasperma f. sp. glycinea, a fungal pathogen to which parsley shows a non-host, hypersensitive resistance response.Abbreviations BMT S-adenosyl-L-methionine: bergaptol O-methyltransferase (EC 2.1.1.-) - 4CL 4-coumarate: CoA ligase (EC 6.1.1.12) - CMT S-adenosyl-L-methionine: caffeate O-methyltransferase (EC 2.1.1.-) - PAL L-phenylalanine ammonia-lyase (EC 4.3.1.5) - PR pathogenesis-related - XMT S-adenosyl-L-methionine: xanthotoxin O-methyltransferase (EC 2.1.1.-)