scholarly journals Electrical activity of the central nervous system of the frog

Careful exploration has been made of the electrical activity of the brain of various mammals (Adrian and Matthews 1934; Gerard, Marshall and Saul 1936; Gerard 1936 a and b ), but there has been very little study of the brains of other vertebrates (Adrian 1931; Umrath and Umrath 1934). The small size and relatively homogeneous cell population of the Amphibian brain offer certain advantages in analysis of the physicochemical factors determining activity; and further, the low metabolism of the poikilothermic brain at room temperature, together with the short distances for oxygen diffusion, suggested the possibility of studying sustained activity in the isolated organ. The present report covers a general exploration of spontaneous electrical changes in the neuraxis of the grass frog ( Rana pipiens ) and bull frog ( R. catesbiana ).

1956 ◽  
Vol 185 (3) ◽  
pp. 601-606 ◽  
Author(s):  
Alan G. Slocombe ◽  
Hudson Hoagland ◽  
Lillian S. Tozian

Lysergic acid diethylamide (LSD), 5-hydroxytryptamine, and adrenochrome were shown to have properties similar to epinephrine in their effects on the spontaneous electrical activity in the brain of the albino rat. The effects of these drugs were shown to be determined by the type of anesthetic used. In Pentothal-anesthetized animals, profound reduction of the electrical activity in both frequency and amplitude was found in response to these drugs, while in ether-anesthetized animals there was no significant effect. There was a tendency for LSD to increase electrical activity when injected following recovery from anesthesia. The significance of this differential response is discussed with respect to structures in the central nervous system primarily affected by ether and Pentothal, and it is suggested that the site of action of these compounds is in Pentothal-sensitive nonspecific pathways. The site of the depressive action of these drugs with Pentothal is further defined by the fact that both cortical and subcortical structures were equally affected, while respiratory and cardio-regulatory centers were not significantly depressed. This implicates one of the lower nonspecific centers with widespread cortical and subcortical projections.


2021 ◽  
Vol 95 ◽  
Author(s):  
E.P.F. de Souto ◽  
A.M. Oliveira ◽  
É.M. Campos ◽  
V.L.R. Vilela ◽  
C.S.L. de Barros ◽  
...  

Abstract The present report describes two cases of infection by Molossinema wimsatti in the brain of Pallas's mastiff bats (Molossus molossus). The first bat was captured and killed by a domestic cat in a suburban area of the municipality of Patos, Paraiba, northeastern Brazil. The second bat was found crawling on the ground in the same area before dying. No gross lesions were found at necropsy. Histology of the central nervous system revealed filarioid nematodes in the brain ventricles and cerebellum. There were adults, subadults and eggs, the latter sometimes containing microfilariae. No inflammatory response was observed in bat 1, while bat 2 presented a mild lymphoplasmacytic meningoencephalitis. Three nematodes were recovered and submitted for parasitological examination. The diagnosis of M. wimsatti infection was based on the histomorphological and parasitological characteristics of the agent and its location in the brain ventricular system of insectivorous bats. The infection likely occurs in other insectivorous bats from South American and Caribbean countries but may be overlooked.


Biology Open ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. bio051797 ◽  
Author(s):  
Aitana M. Castro Colabianchi ◽  
María B. Tavella ◽  
Laura E. Boyadjián López ◽  
Marcelo Rubinstein ◽  
Lucía F. Franchini ◽  
...  

ABSTRACTThe blastula Chordin- and Noggin-expressing (BCNE) center comprises animal-dorsal and marginal-dorsal cells of the amphibian blastula and contains the precursors of the brain and the gastrula organizer. Previous findings suggested that the BCNE behaves as a homogeneous cell population that only depends on nuclear β-catenin activity but does not require Nodal and later segregates into its descendants during gastrulation. In contrast to previous findings, in this work, we show that the BCNE does not behave as a homogeneous cell population in response to Nodal antagonists. In fact, we found that chordin.1 expression in a marginal subpopulation of notochordal precursors indeed requires Nodal input. We also establish that an animal BCNE subpopulation of cells that express both, chordin.1 and sox2 (a marker of pluripotent neuroectodermal cells), and gives rise to most of the brain, persisted at blastula stage after blocking Nodal. Therefore, Nodal signaling is required to define a population of chordin.1+ cells and to restrict the recruitment of brain precursors within the BCNE as early as at blastula stage. We discuss our findings in Xenopus in comparison to other vertebrate models, uncovering similitudes in early brain induction and delimitation through Nodal signaling.This article has an associated First Person interview with the first author of the paper.


2020 ◽  
Author(s):  
Aitana M. Castro Colabianchi ◽  
María B. Tavella ◽  
Laura E. Boyadjián López ◽  
Marcelo Rubinstein ◽  
Lucía F. Franchini ◽  
...  

ABSTRACTThe Blastula Chordin- and Noggin Expressing Center (BCNE) comprises animal-dorsal and marginal-dorsal cells of the amphibian blastula and contains the precursors of the brain and of the gastrula organizer. Previous findings suggested that the BCNE behaves as a homogeneous cell population that depends only on nuclear β-catenin activity but does not require Nodal and segregates into its descendants later, during gastrulation. In this work, we analyzed if the BCNE is already compartmentalized at the blastula stage. In contrast to previous findings, we show that the BCNE does not behave as a homogeneous cell population in response to Nodal antagonists. In fact, we found that the chordin.1 expression in a marginal subpopulation of notochordal precursors indeed requires Nodal input. We also establish that an animal BCNE subpopulation of cells that express both, chordin.1 and sox2 (a marker of pluripotent neuroectodermal cells), and gives rise to most of the brain, persisted at blastula stage after blocking Nodal. Moreover, RT-qPCR analysis showed that chordin.1 and sox2 expression increased at blastula stage after blocking Nodal. Therefore, Nodal signaling is required to define a population of chordin.1+ cells and to restrict the recruitment of brain precursors within the BCNE as early as at blastula stage.


1958 ◽  
Vol 192 (3) ◽  
pp. 453-456
Author(s):  
Jean A. Cerf ◽  
Leon S. Otis ◽  
Sadayuki F. Takagi

The effect of temperature elevation on the electrical activity of the vagal lobe was studied in both intact and isolated goldfish brain. The slow potential changes recorded at room temperature ceased above a critical temperature (about 37°C), and reappeared on cooling. The degree of reversibility of the block was inversely proportional to the duration of heat application and the final temperature of the brain immediately preceding cooling.


1954 ◽  
Vol 100 (418) ◽  
pp. 125-128 ◽  
Author(s):  
J. Elkes ◽  
C. Elkes ◽  
P. B. Bradley

Peripheral neuro-effector sites within and outside the autonomic nervous system form useful reference points for the study of the central effects of some agents. Nevertheless, ready analogies between peripheral neurohumoral mediation, and central synaptic transmission may be grossly misleading, and reliance must solely be placed on data derived from within the central nervous system itself.


Author(s):  
Hannah R. Brown ◽  
Tammy L. Donato ◽  
Halldor Thormar

Measles virus specific immunoglobulin G (IgG) has been found in the brains of patients with subacute sclerosing panencephalitis (SSPE), a slowly progressing disease of the central nervous system (CNS) in children. IgG/albumin ratios indicate that the antibodies are synthesized within the CNS. Using the ferret as an animal model to study the disease, we have been attempting to localize the Ig's in the brains of animals inoculated with a cell associated strain of SSPE. In an earlier report, preliminary results using Protein A conjugated to horseradish peroxidase (PrAPx) (Dynatech Diagnostics Inc., South Windham, ME.) to detect antibodies revealed the presence of immunoglobulin mainly in antibody-producing plasma cells in inflammatory lesions and not in infected brain cells.In the present experiment we studied the brain of an SSPE ferret with neutralizing antibody titers of 1:1024 in serum and 1:512 in CSF at time of sacrifice 7 months after i.c. inoculation with SSPE measles virus-infected cells. The animal was perfused with saline and portions of the brain and spinal cord were immersed in periodate-lysine-paraformaldehyde (P-L-P) fixative. The ferret was not perfused with fixative because parts of the brain were used for virus isolation.


Author(s):  
S.S. Spicer ◽  
B.A. Schulte

Generation of monoclonal antibodies (MAbs) against tissue antigens has yielded several (VC1.1, HNK- 1, L2, 4F4 and anti-leu 7) which recognize the unique sugar epitope, glucuronyl 3-sulfate (Glc A3- SO4). In the central nervous system, these MAbs have demonstrated Glc A3-SO4 at the surface of neurons in the cerebral cortex, the cerebellum, the retina and other widespread regions of the brain.Here we describe the distribution of Glc A3-SO4 in the peripheral nervous system as determined by immunostaining with a MAb (VC 1.1) developed against antigen in the cat visual cortex. Outside the central nervous system, immunoreactivity was observed only in peripheral terminals of selected sensory nerves conducting transduction signals for touch, hearing, balance and taste. On the glassy membrane of the sinus hair in murine nasal skin, just deep to the ringwurt, VC 1.1 delineated an intensely stained, plaque-like area (Fig. 1). This previously unrecognized structure of the nasal vibrissae presumably serves as a tactile end organ and to our knowledge is not demonstrable by means other than its selective immunopositivity with VC1.1 and its appearance as a densely fibrillar area in H&E stained sections.


Author(s):  
J.E. Johnson

Although neuroaxonal dystrophy (NAD) has been examined by light and electron microscopy for years, the nature of the components in the dystrophic axons is not well understood. The present report examines nucleus gracilis and cuneatus (the dorsal column nuclei) in the brain stem of aging mice.Mice (C57BL/6J) were sacrificed by aldehyde perfusion at ages ranging from 3 months to 23 months. Several brain areas and parts of other organs were processed for electron microscopy.At 3 months of age, very little evidence of NAD can be discerned by light microscopy. At the EM level, a few axons are found to contain dystrophic material. By 23 months of age, the entire nucleus gracilis is filled with dystrophic axons. Much less NAD is seen in nucleus cuneatus by comparison. The most recurrent pattern of NAD is an enlarged profile, in the center of which is a mass of reticulated material (reticulated portion; or RP).


Author(s):  
Grazia Tagliafierro ◽  
Cristiana Crosa ◽  
Marco Canepa ◽  
Tiziano Zanin

Barnacles are very specialized Crustacea, with strongly reduced head and abdomen. Their nervous system is rather simple: the brain or supra-oesophageal ganglion (SG) is a small bilobed structure and the toracic ganglia are fused into a single ventral mass, the suboesophageal ganglion (VG). Neurosecretion was shown in barnacle nervous system by histochemical methods and numerous putative hormonal substances were extracted and tested. Recently six different types of dense-core granules were visualized in the median ocellar nerve of Balanus hameri and serotonin and FMRF-amide like substances were immunocytochemically detected in the nervous system of Balanus amphitrite. The aim of the present work is to localize and characterize at ultrastructural level, neurosecretory neuron cell bodies in the VG of Balanus amphitrite.Specimens of Balanus amphitrite were collected in the port of Genova. The central nervous system were Karnovsky fixed, osmium postfixed, ethanol dehydrated and Durcupan ACM embedded. Ultrathin sections were stained with uranyl acetate and lead citrate. Ultrastructural observations were made on a Philips M 202 and Zeiss 109 T electron microscopy.


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