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Biomedical subjects

M Satou

Publications and source records attributed to M Satou.

At least 91 records · Page 5Linked to original sources
PubMed1985

An HRP study of afferent connections of the supracommissural ventral telencephalon and the medial preoptic area in himé salmon (landlocked red salmon, Oncorhynchus nerka).

The supracommissural ventral telencephalon and the medial preoptic area have been shown to play important roles in the sexual behavior of himé salmon (landlocked red salmon, Oncorhynchus nerka). In the present study, the sites of neurons projecting to these regions were examined by means of the retrograde horseradish peroxidase (HRP) tracing method. The morphology of neurons in these sites of origin was also studied by means of the Golgi method. The nucleus preopticus periventricularis and the rostral part of nucleus preopticus (NPP-rNPO) received bilateral projections from the middle parts of the area ventralis telencephali pars ventralis (Vv) and the area ventralis telencephali pars dorsalis (Vd), NPP and lateral part of the preoptic area (LPOA), ipsilateral projections from the caudal part of Vv, nucleus anterioris periventricularis (NAPv), nucleus ventromedialis thalami (NVM) at the level of the posterior commissure, nucleus lateralis tuberis pars medialis (NLTm), nucleus anterior tuberis (NAT), nucleus saccus vasculosus (NSV), nucleus recessus posterioris (NRP) and midbrain tegmentum (TG), and a projection from the nucleus posterior tuberis (NPT), which is situated on the midline of the brain. The area ventralis telencephali pars supracommissuralis and neighboring caudal ventral telencephalon (Vs-cV) received ipsilateral projections from almost all parts of the Vv, the middle and caudal parts of Vd, almost all parts of the NNP, the NPO at the level between the habenula and the posterior commissure, and the rostral part of the nucleus dorsomedialis thalami (NDM). The Vs-cV also received a projection from NPT. These findings seem to give anatomical bases for understanding the neural mechanisms involved in sexual behavior as well as neuroendocrine functions.

Afferent Pathways↗
PubMed1985

Ganglion cells of the terminal nerve: morphology and electrophysiology.

The ganglion cells of the terminal nerve (TN cells) in the carp were identified using intracellular recording and staining techniques. The TN cells showed characteristic location and morphology as well as characteristic responses after electrical shocks to the olfactory nerve and tracts. These features of the TN cells were distinct from those of the mitral or other cells in the olfactory bulb.

Animals↗
PubMed1985

Tongue-muscle-controlling motoneurons in the Japanese toad: topography, morphology and neuronal pathways from the 'snapping-evoking area' in the optic tectum.

As a step to clarifying the neural bases for the visually-guided prey-catching behavior in the toad, special attention was paid to the flipping movement of the tongue. Tongue-muscle-controlling motoneurons were identified antidromically, and their topographical distribution within the hypoglossal nucleus, the morphology, and the neuronal pathways from the optic tectum including the 'snapping-evoking area' (see below) to these motoneurons were investigated in paralyzed Japanese toads using intracellular recording techniques. The morphology of motoneurons innervating the tongue-protracting or retracting muscles (PMNs or RMNs respectively) was examined by means of intracellular-staining (using HRP/cobaltic lysine) and retrograde-labeling (using cobaltic lysine) methods. Both PMNs and RMNs showed an extensive spread of the branching trees of dendrites; 4 dendritic fields were distinguished: lateral/ventrolateral, dorsal/dorsolateral, medial, and in some motoneurons, contralateral dendritic fields, although there was a tendency for the dorsal/dorsolateral dendritic field to be less extensive in the PMNs than in the RMNs. The axons of both PMNs and RMNs arose from thick dendrites, ran in a ventral direction without any axon-collaterals branching off, and then entered the hypoglossal nerve. The PMNs and RMNs were distributed topographically within the hypoglossal nucleus; the RMNs were located rostrally within the nucleus, whereas the PMNs were located more caudally within it. In about 3/4 of the RMNs tested, depolarizing potentials [presumably the excitatory postsynaptic potentials (EPSPs)], on which action potentials were often superimposed, were evoked by electrical stimuli applied to the nerve branch innervating the tongue protractor. These EPSPs were temporally facilitated when the electrical stimuli were applied at short intervals (10 ms). Both PMNs and RMNs showed hyperpolarizing potentials (IPSPs) in response to single electrical stimuli of various intensities (10-200 microA) applied to the 'snapping-evoking area' (lateral/ventrolateral part of the optic tectum) on either side. These IPSPs were facilitated after repetitive electrical stimulations at short intervals (10 ms) and of weaker intensities (down to 10 microA); i.e., a temporal facilitation of the IPSPs was observed. On the other hand, large and long-lasting EPSPs which prevailed over the underlying IPSPs were evoked after repetitive electrical stimulations (a few pulses or more) at short intervals (10 ms) and of stronger intensities (generally 90 microA or more); thus, a temporal facilitation of the EPSPs was also observed.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1985

The antidromic activation of tectal neurons by electrical stimuli applied to the caudal medulla oblongata in the toad, Bufo bufo L.

In order to specify the tectal projection to the bulbar/spinal regions, the antidromic responses of the physiologically identified tectal neurons as well as the gross antidromic field responses in the optic tectum to electrical stimuli applied to the caudal medulla were examined in the paralyzed common toad, Bufo bufo. The antidromic field potential was recorded in the optic tectum in response to electrical stimuli applied to the ventral paramedian portion of the contralateral caudal medulla (where the crossed tecto-spinal pathway of Rubinson (1968) and Lázár (1969) runs), but generally not when they were applied to various parts of the ipsilateral caudal medulla. The antidromic field potential was largest at the superficial part of Layer 6 or at the border between Layers 6 and 7 of the optic tectum, indicating that neurons in these layers project to the contralateral caudal medulla. Mapping experiments of the antidromic field potential over the optic tectum showed that the antidromic field potential was recorded mainly in the lateral part of it, indicating that this part of the optic tectum is the main source of projection neurons to the contralateral caudal medulla. Various classes of tectal neurons as well as retinal ganglion neurons were identified from the characteristics of the response properties to moving visual stimuli and the properties of the receptive fields. Of these, the Class T1, T2, T3, T4, T5(1), T5(2), T5(3), and T5(4) tectal neurons were activated antidromically by stimuli applied to the contralateral caudal medulla. Only a limited proportion of the Class T5(1) neurons was activated antidromically by stimuli applied to the ipsilateral caudal medulla. On the other hand, the Class T7 and T8 neurons, as well as the Class R2, R3, and R4 retinal neurons, were not activated antidromically by stimuli applied to the caudal medulla of either side. These results suggest a possibility that these tectal neurons which project to the medullary regions form the substrate of the sensorimotor interfacing and contribute to the initiation or coordination of the visually guided behavior, such as prey-catching.

Animals↗
PubMed1985

An electromyographic analysis of electrically-evoked prey-catching behavior by means of stimuli applied to the optic tectum in the Japanese toad.

As a step toward elucidating the tectal-controlling functions for generating the prey-catching motor pattern, electrically-evoked "snapping" (the final consummatory phase of the prey-catching sequence) by means of stimuli applied to the optic tectum was analyzed using electromyographic methods in freely-moving Japanese toads. Electromyographic activities were recorded from the following 7 muscles in the head region (the presumed "snapping"-related muscles): M. depressor mandibulae, M. temporalis, M. sternohyoideus, M. geniohyoideus, M. genioglossus, M. hyoglossus, and M. submentalis. It was found that the characteristic activities evoked in these muscles were associated with jaw/tongue movements during the electrically-evoked "snapping". All of these muscles, except for sternohyoideus and geniohyoideus muscles, were activated in an all-or-nothing manner which corresponded to the elicitation of the electrically-evoked "snapping". It was suggested that such an all-or-nothing character may reflect an all-or-nothing property of the neuronal circuits for generating the prey-catching motor-pattern.

Animals↗
PubMed1985

Efferents from the supracommissural ventral telencephalon in the hime salmon (landlocked red salmon, Oncorhynchus nerka): an anterograde degeneration study.

Efferents from the area ventralis telencephali pars supracommissuralis (Vs) of hime salmon (landlocked red salmon, Oncorhynchus nerka) were studied using anterograde degeneration methods. It was found that Vs sends intratelencephalic fibers bilaterally to the internal cell layer of the olfactory bulb and wide areas of telencephalon, while it sends extratelencephalic fibers bilaterally to habenulae, inferior lobes and midbrain tegmenti through medial and lateral forebrain bundles and lateral preoptic area. A possibility was pointed out that some of these extratelencephalic projections are involved in the pathway controlling the sexual behavior which are suggested from behavioral experiments.

Animals↗
PubMed1984

A field-potential study of centripetal and centrifugal connections of the olfactory bulb in the carp, Cyprinus carpio (L).

The projection areas of mitral cell axons in the lateral (LOT) and medial (MOT) olfactory tracts and the pathways of two groups of centrifugal fibers (with fast and slow conduction velocities) to the olfactory bulb were studied in the carp using the field potential method. Mitral cell axons of the LOT and those of the MOT projected to the overlapping areas in the bilateral telencephalon and preoptic area (POA), the contralateral MOT, and the nucleus posterior tuberis (NPT) in the diencephalon. However, the precommissural, ventromedial part of the ipsilateral telencephalon received the projection only from mitral cell axons of the MOT, not from those of the LOT. No projection was detected in the contralateral LOT and the contralateral olfactory bulb. The distribution of the fast and slow centrifugal fibers and/or their cells of origin were similar to each other. They were distributed bilaterally in the telencephalon and POA, in the NPT, and contralateral LOT and MOT. These areas overlapped with the projection areas of the mitral cell axons considerably. The results support and extend those obtained from anatomical studies.

Animals↗
PubMed1984

Telencephalic and preoptic areas integrate sexual behavior in hime salmon (landlocked red salmon, Oncorhynchus nerka): results of electrical brain stimulation experiments.

Various patterns of sexual behavior were evoked in freely swimming hime salmon by electrical stimulation of specific loci in the telencephalon and the preoptic area (POA) using chronically implanted electrodes. Furthermore, co-ordinated sexual behavior corresponding to stages of the natural spawning sequence was elicited from some of these brain regions. These results suggest that (1) sexual behavior is integrated in specific parts of the telencephalon and POA, and (2) within these regions there is a hierarchy of neural systems which mediate progressively more complete components of normal sexual behavior.

Animals↗
PubMed1984

Involvement of the telencephalic hemispheres and the preoptic area in sexual behavior of the male goldfish, Carassius auratus: a brain-lesion study.

To locate the brain areas involved in sexual behavior, the effects on male sexual behavior of localized electrolytic lesions in various parts of the telencephalic hemispheres and the preoptic area and of gross ablations of parts of the telencephalic hemispheres were examined in goldfish. All three patterns of male sexual behavior examined (following, butting , and spawning) were severely impaired after bilateral lesions confined to the area ventralis telencephali pars supracommissuralis and/or posterior parts of the area ventralis telencephali pars ventralis (Vs- pVv ), the nucleus preopticus periventricularis (NPP), the lateral forebrain bundle ( LFB ), or the medial forebrain bundle (MFB). On the other hand, sexual behavior was almost unaffected after bilateral ablations of the anterior part or lateral and dorsal parts of the telencephalic hemispheres (AT or LT-DT). Bilateral lesions confined to the area ventralis telencephali pars dorsalis (Vd), the area ventralis telencephali pars postcommissuralis (Vp), the area dorsalis telencephali pars centralis (Dc), the nucleus preopticus (NPO), or the lateral preoptic area (LPA) also had almost no effect on sexual behavior. These results indicate that a particular site in the ventral part of the telencephalic hemispheres (Vs- pVv ) and the anterior part of the preoptic area (NPP) play important roles in the sexual behavior of male goldfish. It was suggested that facilitatory influences from these areas are transmitted through the LFB and/or the MFB.

Animals↗
PubMed1983

Monosynaptic and disynaptic activation of pyriform cortex neurons by synchronous lateral olfactory tract volleys in the rabbit.

To elucidate the organization of synaptic inputs to pyriform cortex neurons, intracellular and extracellular responses of single units were analyzed in urethane-anesthetized rabbits. The lateral olfactory tract (LOT) or the olfactory bulb (OB) was electrically stimulated. Intracellular recordings revealed two types of cells (type I and type II cells), according to the types of EPSP evoked by the LOT or OB shock. The EPSP in the type I cells had shorter latencies (0.0 to 0.9 ms) from the onset of the component 2 (C2) wave of the field potential (which signals the onset of the synaptic depolarization of the apical dendrites of the pyramidal cells in the PC), and that in the type II cells had longer latencies (1.0 to 6.0 ms). A conditioning LOT or OB shock did not suppress the testing EPSP in the type I cells, whereas the conditioning stimulation greatly suppressed the testing EPSP in most of the type II cells. Extracellular recordings from units responding synaptically to the LOT or OB shock revealed a group of units which had short latencies (0.7 to 1.9 ms) of spike discharges. Those units, which were likely to be the same cells as the type I cells, are believed to mediate excitatory synaptic inputs to the type II cells. On the basis of these results, we concluded that type I cells are monosynaptically activated by LOT volleys, whereas type II cells are activated di- or polysynaptically by way of a relay from type I cells. The type I cells were recorded in both the superficial and the deep parts of the pyriform cortex, although they were recorded more frequently in the superficial part. On the other hand, most of the type II cells were recorded in the deep part of the PC. These results support and extend the previous model, in which the monosynaptically activated superficial pyramidal cells give rise to excitatory inputs to other pyramidal cells and neurons in deep layers.

Animals↗
PubMed1983

Neuronal pathways for activation of inhibitory interneurons in pyriform cortex of the rabbit.

The neuronal pathways responsible for the fast inhibitory postsynaptic potentials (IPSPs) elicited in principal cells in the pyriform cortex (PC) by volleys from the olfactory bulb (OB), the lateral olfactory tract (LOT), the anterior commissure (AC), and the deep-lying structures of the PC (DPC) were studied in the rabbit. The central latencies of the fast IPSPs (measured from the onset of the monosynaptic excitatory postsynaptic potential (EPSP) elicited by volleys through the LOT) ranged between 3.0 and 9.3 ms (5.5 +/- 1.3 (SD) ms; n = 54) in the case of OB shocks and between 4.5 and 6.5 ms (5.1 +/- 0.7 (SD) ms; n = 7) in the case of LOT shocks. The onset latencies of the fast IPSPs were between 2.5 and 11.8 ms (5.1 +/- 1.8 (SD) ms; n = 66) in the case of DPC shocks and between 3.5 and 10.1 ms (5.8 +/- 1.5 (SD) ms; n = 61) in the case of AC shocks. The conditioning OB or LOT shocks almost completely eliminated the LOT-evoked fast IPSP when the testing shock was applied at the peak period of the conditioning slow IPSP. The conditioning OB shocks also eliminated the initial part of the OB-evoked fast IPSP, leaving the later part of the fast IPSP almost unchanged. Thus, the onset latency of the OB-evoked fast IPSP was lengthened by 7.1 +/- 2.9 (SD) ms (n = 35) by the conditioning OB shock. The conditioning OB or DPC shocks left the peak amplitude of the DPC-evoked fast IPSP almost unaffected. Similarly, the conditioning OB or AC shocks left the peak amplitude of the AC-evoked fast IPSP almost unaffected. The conditioning OB, DPC, or AC shocks had only a slight influence on the onset latency of the DPC- or AC-evoked fast IPSPs. Rhythmical steps at intervals of 3-5 ms were observed in the rising phase of the OB-evoked fast IPSP. This was interpreted as a result of a repetitive impingement of interneuronal discharges on the impaled cells. Spatial facilitation was observed among the fast IPSPs evoked by volleys from the OB, DPC, and AC when shocks were applied at suitable intervals. A slight facilitation was also seen between the LOT-evoked fast IPSP and the DPC- or AC-evoked fast IPSP. These results were interpreted as a result of the convergence of excitatory synaptic inputs onto the presumed inhibitory interneurons from the four structures of the brain. A temporal facilitation of the fast IPSPs was observed when the OB, DPC, or AC shocks were applied repetitively at short intervals. This suggests a temporal facilitation of the spike discharges of the presumed inhibitory interneurons under similar conditions. From these results, criteria were determined for identifying the inhibitory interneurons.

Animals↗
PubMed1983

Interneurons mediating fast postsynaptic inhibition in pyriform cortex of the rabbit.

Interneurons mediating the fast IPSPs in principal cells in the pyriform cortex (PC) of the rabbit were searched for using criteria derived from the analysis of the properties of the fast inhibitory postsynaptic potentials (IPSPs). Thirty units were identified as inhibitory interneurons. The interneurons were activated synaptically by volleys from the olfactory bulb (OB), the lateral olfactory tract (LOT), the anterior commissure (AC), and deep-lying structures of the PC (DPC). The interneurons showed a tendency to discharge repetitively in response to shocks applied to these structures of the basal forebrain (OB, LOT, AC, and DPC). The conditioning OB shocks eliminated the testing LOT-evoked discharges of the interneurons. The conditioning OB shocks eliminated the initial part of the testing OB-evoked discharges, leaving the later part relatively unchanged. On the other hand, the conditioning OB shocks did not completely eliminate the testing DPC- or AC-evoked discharges. A temporal facilitation of discharges in the interneurons was observed in response to volleys from the OB, DPC, or AC. A spatial facilitation of discharges in the interneurons was observed in response to a combination of shocks applied to the OB, DPC, and AC. The interneurons were recorded at depths 525-2,755 microns deep to the turnover point of the component 2 wave of field potentials evoked by volleys through the LOT fibers. They were located mostly in the deeper part of layer III of the PC. Intracellular recordings from the presumed inhibitory interneurons showed that OB stimulation elicited two successive excitatory postsynaptic potentials (EPSPs) on which the bursting discharges were superimposed. These EPSPs were followed by a long-lasting hyperpolarizing potential. A comparison of the latencies of the antidromic activation of the principal cells and the synaptic activation of the inhibitory interneurons following OB or DPC stimulation suggested that the inhibitory interneurons are activated at least partly through the axon collaterals of the principal cells, which project their main axons to the OB or DPC. A circuit diagram was proposed for the neuronal pathways responsible for the fast IPSPs of principal cells in the PC.

Animals↗
PubMed1979

Neuromuscular blocking potency of fazadinium in man.

The study was designed to compare the recovery rates of fazadinium and four other commonly used competitive muscle relaxants in forty patients and eight volunteers. One-fifth to 1/10 of the clinical doses of the muscle relaxants were diluted in 20 ml of saline and injected intravenously at the wrist after inflation of a pneumatic tourniquet on the upper arm. After 3 min the tourniquet was released and the recovery time of twitch tension from 25 to 75% of the control determined. Evoked force of middle finger adduction was measured at a frequency of 0.2 Hz. The mean 25-75% recovery times of twitch tension for tubocurarine, pancuronium, alcuronium, gallamine and fazadinium were 14.20 +/- 1.42, 12.30 +/- 1.02, 10.12 +/- 0.77, 10.07 +/- 1.12 and 9.90 +/- 0.87 min, respectively. The authors conclude that the dissociation rate of fazadinum from the receptor of the motor endplate appears to be the fastest among the competitive muscle relaxants studied in man.

Adolescent↗