[Role of nitric oxide in the mechanisms of formation of reflex vasomotor responses].

This review focuses on modem data concerning the role of nitric oxide (NO) in the mechanisms of vasomotor regulation. On the background of the literature data and own experimental results, we have discussed some questions of NO integration into transmission of impulses in central and autonomic nervous system under condition of realization of cardiogenic and sinocarotid pressor and depressor reflexes, reflectory vasomotor responses formation under acute myocardial ischemia. According to literature and own functional and morphological data we suggest species differences in NO participations in mechanisms of reflex self--regulation of circulation.

[Sources of cortical, hypothalamic and spinal serotoninergic projections: topical organization in the dorsal Raphe nucleus]. / Istochniki kortikal'nykh, gipotalamicheskikh i spinal'nykh serotoninergicheskikh proektsii: topicheskaia organizatsiia v predelakh dorsal'nogo iadra shva.

Distribution of primuline, fast blue, fluoro-gold and nuclear yellow-labelled monoamine-containing cells in periventricular gray and dorsolateral tegmentum (including locus coeruleus) was studied in the rat after injection of these fluorochromes into the frontal cortex, hypothalamus and spinal cord. Combination of monoamine fluorescence method and retrograde cell-labelling was used. Two big groups of serotonin-positive cells projecting into the upper thoracic spinal segments were found in dorsomedial zone of the dorsal raphe. Part of these units also had divergent axon projections to the frontal cortex. Such cellular arrangement allows a supposition that analgetic effects of dorsal raphe stimulation can be partially based on the direct participation of this structure in the descending control at the spinal level. Neurones, sources of cortical projections are intermingled with the cells projecting to the hypothalamus but some topical differentiation can be distinguished. Neurotransmitter and neuroregulatory roles of separate cortical and hypothalamic projections of serotonin-containing neurons of the dorsal raphe cells is discussed.

[The bevelling of microelectrodes by vibration without using a special generator]. / Zatochka mikroélektrodov metodom vibratsii bez ispol'zovaniia spetsial'nogo generatora.

An original set-up replacing generator of sound frequencies is suggested. This set-up connected with AC current of 50 Hz frequency can be used as a power source to the electromagnetic vibrator with the frequency of the mechanical resonance of 200 Hz.

[Ultrastructural characteristics of callosal neurons in deep layers of the primary auditory cortex (AI) in cat]. / Ul'trastrukturnye kharakteristiki kallozal'nykh neironov glubokikh sloev pervoi slukhovoi oblasti (SI) kory mozga koshki.

An electron microscope study of retrogradely labelled nonpyramidal neurons has been carried out in layers V-VI of the primary auditory cortex (AI) after HRP injections into the contralateral AI of cats. From 2 to 9 synapses were usually revealed on somatic profiles of these callosal neurons. Synapses occupied 15.8 +/- 1.7% (on the average) of the somatic surface of these neurons. All of the revealed synapses on the somata of these callosal neurons had symmetric contacts and were formed by axon terminals with small elongated synaptic vesicles. An average length of these synaptic contacts in sections was 1.6 +/- 0.1 mm. HRP-labelled axon terminals of callosal fibres in layers V-VI contained round synaptic vesicles and formed asymmetric synapses on spines and dendrites. Possible functional significance of axo-somatic synapses in formation of impulsation patterns of the callosal neurons is discussed.

[Correlations between thalamic projections to different areas of the parietal association cortex of the cat]. / Sootnosheniia talamicheskikh proektsii v razlichnye chasti temennoi assotsiativnoi kory koshek.

Projections of thalamic neurons to parietal association cortex of cat were examined by means of the retrograde axonal transport of fluorescent dyes (primuline and fast blue). It has been demonstrated that a dorsal part of the pulvinar (PL) and a dorsal part of the caudal area of the lateral posterior nucleus (LP) projected mostly to the middle suprasylvian gyrus (MSSG), while a ventral part of PL and a ventral part of the rostral area of LP--to the rostral suprasylvian gyrus (RSSG). Double labelled neurons were found in PL, LP, suprageniculatus, anterior ventral, ventral lateral as well as in the central lateral, paracentral and central medial nuclei after injections of two different dyes into MSSG and RSSG. Topic organization of sources of cortical projections from the PL--LP complex can probably provide a high level of discrimination of visual signals by single cortical neurons. At the same time during integration of information of a different subcortical origin RSSG and MSSG act, probably, in concord to a considerable extent, that suggests insufficient differentiation of RSSG and MSSG corresponding approximately to cortical areas 5 and 7 of cat.

[The ultrastructural characteristics of the pyramidal callosal neurons of layer III in the primary auditory area (A1) of the cat cortex]. / Ul'trastrukturnye kharakteristiki piramidnykh kallozal'nykh neironov III sloia pervoi slukhovoi oblasti kory (A1) u koshki.

An electron microscope study of retrogradely labelled pyramidal neurons in layer III of the primary auditory cortex (AI) after HRP injections into the contralateral AI has been carried out in cats. From 4 to 10 synapses were usually revealed on somatic profiles of these callosal neurons. Synapses occupied 20.0% of the somatic surface of these neurons. All of the revealed synapses on the somata of callosal neurons had symmetric contacts and were formed by axon terminals with small elongated synaptic vesicles. Average length of these synaptic contacts was 1.6 microns. In layer III anterogradely labelled terminals of callosal fibres were also revealed. The majority of them contained large round synaptic vesicles and formed asymmetric contacts on spines. Three labelled axon terminals with small elongated vesicles were found to form symmetric axo-somatic synapses on callosal neurons of layer III.

[The morphological characteristics of the callosal neurons of the first auditory area of the cortex (AI) in the cat]. / Morfologicheskaia kharakteristika kallozal'nykh neironov pervoi slukhovoi oblasti kory (AI) u koshki.

Cortical stratification of callosal neurons in the primary auditory cortex (AI) of cat was studied by means of horseradish peroxidase (HRP). Two main groups of callosal neurons were revealed. The first group comprising 60% of all AI callosal neurons consisted predominantly of layer III large pyramidal neurons. Average area of these pyramidal neuron perikaryon profiles was 261.8 +/- 8.8 microns2. The number of HRP-labelled callosal neurons in layer III was 22% of all cells in this layer. The second group comprising 27% of all AI callosal neurons consisted mainly of large cells of layers V and VI which could not be classified as pyramidal neurons. Average area of these nonpyramidal neuron perikaryon profiles was 250.3 +/- 8.4 microns 2. In layer I callosal neurons were not revealed, in layers II and IV accordingly 6% and 7% of AI callosal neurons were located.

[Identification of catecholamines in the rat brain and mollusk tissues using semithin slices and retrograde staining]. / Identifikatsiia na polutonkikh srezakh katekholaminov i retrogradnoi metki v mozgu krysy i tkaniiakh molliuskov.

The suggested technique allows revealing the transport-specific dye (primulin) and catecholamine fluorescence simultaneously in the same cell of brain. Intense fluorescence is observed when brain tissue is quickly dehydrated and embedded in the epoxy resin. The same method is suggested for the identification of catecholamines in the embryonal and juvenile tissues of gastropod Lymnaea stagnalis (Mollusca Pulmonata) without using of primulin dye.

[A method of rapid beveling of microelectrodes using vibration]. / Metod bystroi zatochki mikroelektrodov s pomoshch'iu vibratsii.

The new technique is suggested for a rapid bevelling of glass and metallic microelectrodes by means of ends' friction on the fine-grained surface of a quartz plate vibrating at a frequency of the mechanical resonance of the system.

[Distribution of norepinephrine-containing neurons projecting to the parietal associative cortex and spinal cord in the cat locus coeruleus]. / Raspredelenie v golubom piatne koshki noradrenalinsoderzhashchikh neironov, proetsiruiushchikhsia v temennuiu assotsiativnuiu koru i spinnoi mozg.

The distribution of neurons projecting to the parietal associative cortex and spinal cord in the locus coeruleus (LC) of the cat was examined by the retrograde transport of the horseradish peroxidase (HRP) and catecholamine histofluorescence technique. It was demonstrated that neurons projecting to the parietal cortex were localized predominantly in the dorsal LC and the most dense labeling was observed at the coronal section corresponding to frontal plane P-1. Neurons projecting to the spinal cord were concentrated in the ventral LC and the largest quantity of labeled neurons was found in the frontal plane P-3. Microinjections of HRP into the parietal cortex and spinal cord also caused intense retrograde labeling of neurons in the reticular formations of mesencephalon, pons varolii and medulla oblongata. Coeruleo-cortical and coeruleo-spinal projection neurons formed in the LC two partially overlapping cellular populations which could not be differentiated according to morphologic characteristics of their cells. It was concluded that the parietal associative cortex of cat as well as spinal cord had direct afferent inputs both from the LC and from the reticular formation.

[Brain stem neurons of the guinea pig that form projections into the ampullae of the anterior, lateral and posterior semicircular canals]. / Neirony stvola mozga morskoi svinki, obrazuiushchie proektsii v ampuly perednego, lateral'nogo i zadnego polukruzhnykh kanalov.

Brain stem neurons projecting to the ampullae of anterior, lateral and posterior semicircular canals (vestibular efferent neurons) were identified in guinea pigs using, retrograde labelling with horseradish peroxidase. Two groups of such neurons located bilaterally dorsal and ventral to the facial nerve trajectory were classified. A dorsal group contained vestibular efferent neurons to all three canals; these units were located at all the levels of the subependymal granular layer of the floor of the 4th ventricle lateral to the facial nerve genu and abducens nerve nucleus. Vestibular efferent neurons of the ventral group were distributed within different parts of parvocellular and rostral part of the caudal pontine reticular nucleus. Heterogeneity of organization of the vestibular efferent system of semicircular canal ampullae according to cell location and their morphological characteristics are discussed.

[Distribution in the diencephalon of the rat of retrogradely primuline-labelled dopamine-containing neurons forming spinal projections]. / Raspredelenie v promezhutochnom mozge krysy retrogradno mechennykh primulinom dofaminsoderzhashchikh neironov, obrazuiushchikh spinal'nye proektsii.

Distribution of primuline-labeled dopamine-containing neurons in the rat diencephalon following injection of fluorochrome into upper thoracic spinal cord was studied using a combination of catecholamine fluorescence method and retrograde cell-labeling. It was shown that only neurons of group A11 located in the dorsal hypothalamus and caudal thalamus give rise to the spinal projections. Non-catecholamine cells were also labeled in this region. Group A11 comprised 173 +/- 4 catecholamine-containing neurons. Most of them (up to 86%) were retrogradely labeled with primuline. The number of labeled dopamine-containing neurons increased in the rostro-caudal direction. Possible functional role of the dopaminergic diencephalon-spinal neuronal system is discussed.