[A pharmacological analysis of the GABA-ergic system of the primordial hippocampus in the frog Rana temporaria]. / Farmakologicheskii analiz GAMK-ergicheskoi sistemy primordial'nogo gippokampa liagushki Rana temporaria.

The data on evoked potentials (EP) in the frog primordial hippocampus during the surface application of gamma-aminobutyric acid (GABA), beta-alanine and aminooxyacetic acid in the region of EP recording are presented. These results in the aggregate with the earlier described effects of picrotoxin, bicuculline, muscimol, baclofen (on EP) and GABA (on intracellular potentials) permit to suggest the presence of GABA-ergic inhibitory system and two types of GABA receptors in the frog primordial hippocampus.

[Effect of ultrasound on the membrane potential and embryonic development of sea urchin eggs]. / Vliianie ul'trazvuka na membrannyi potentsial i émbrional'noe razvitie iaitsekletok morskogo ezha.

Eggs of sea urchin Strongylocentrotus intermedius were exposed to continuous wave ultrasonic energy at a frequency of 2 MHz for 3 min. Ultrasonic treatment results in the appearance of monstrous embryos that die at the latest stages of their development. The number of dead embryos sharply grows with the increase in the spatial average intensity from 0.4 W/cm2 up to 1.6 W/cm2, when it comprises 100%. Dramatic decrease from 99% to 17% in the absolute value of transmembrane potential for both fertilized and unfertilized eggs was observed after ultrasonic treatment. These results seem to be caused by the action of stable cavitation. The given estimations show that for ultrasonic intensities more than 0.2 W/cm2 and providing the presence of gaseous bubbles in the vicinity of eggs shell the value of shear stress in an egg shell becomes great enough to cause the cytoplasmic gel fragmentation.

[The neurotropic action of kavinton]. / Issledovanie neirotropnogo deistviia kavintona.

The presence of the neurotropic component in cavinton effect was shown as a result of the analysis of the changes in evoked potentials of the frog primordial hippocamp, the surviving slices of the mouse hippocamp and the neuronal activity of the rabbit visual cortex pyramidal neurons at different routes of administration of apovincaminic acid ethyl ether (cavinton).

[2 types of GABA receptors in the intact olfactory bulb and primordial hippocampus of the frog: the pharmacological data]. / Dva tipa GAMK-retseptorov v intaktnoi oboniatel'noi lukovitse i primordial'nom gippokampe liagushki: farmakologicheskie dannye.

The in vivo effects of (+/-) baclofen (10(-6)-10(-4) M), muscimol (10(-5)-10(-4) M), and (+) bicuculline (10(-4)-10(-3) M) applications on evoked potentials in the olfactory bulb (OB) and primordial hippoccamp (PH) were studied in frogs. Baclofen was found to decrease drastically postsynaptic components of OB orthodromic potential and to slightly increase OB antidromic potential. Muscimol decreased only the second component of OB orthodromic potential and OB antidromic potential. Baclofen and muscimol decreased all the components of PH orthodromic potential, but for the first positive one. All the effects were reversible and dose-dependent. Bicuculline antagonized muscimol effects, without affecting baclofen effects in both structures under study. The results suggest the presence of two types of GABA-receptors in OB and PH of frogs. GAGAB-receptors are shown to be located on the primary olfactory afferents and to be responsible for presynaptic inhibition in OB.

[Visual projections in the forebrain of the carp Cyprinus carpio]. / Zritel'nye proektsii v perednem mozgu karpa Cyprinus carpio.

In the carp C. carpio, studies have been made on the evoked potentials (EP) in the-forebrain elicited by electrical stimulation of contralateral (with respect to the midbrain tectum) nerve. The most high-amplitude and short-latency EP were recorded in the rostro-lateral part of the forebrain at the depth of 1,000-1,500 mu. According to the topographical nomenclature of cyprinid telencephalon, this region corresponds to the area dorsalis telencephali pars lateralis, whereas according to classic comparative neuroanatomical nomenclature it may be defined as the primordium hippocamp or primordium piriform zone. Comparison of the EP in the telencephalon with those in the midbrain tectum suggests active nature of the former.