Professor:

Koki Ohno

Visiting Professor :

Toshiaki Takaki

1. Gamma-band population oscillations in a neural network
2. Inhibitory synaptic transmission and the hyperexcitability of the brain
   ( Collaborated with Y. Fueta & K. Fukata ,Sch. of Health Sci., UOEH)
3. Fiber-optic EEG and ECG monitoring instruments in the operating room

Gamma-band oscillation 40 Hz Ach receptor

inhibitory synapse optic-fiber transmission

1. Gamma-band population oscillations in a neural network

   We found carbachol (CCh)-driven gamma-band (~40Hz) population
   oscillations in mouse hippocampal CA3. While the oscillations were
   most obvious and reproducible in genetically seizure-susceptible El
   mice, we also observed these oscillations in ddY (a mother strain of
   El) and BALB/c mice, suggesting that the CCh-driven gamma-band
   oscillations are common phenomena in mouse hippocampi.
   The characteristic oscillations were reproduced by a muscarinic receptor
   agonist bethanechol and completely blocked by the antagonist atropine ;
   nicotine had no effect up to 100 mM.
   In addition, an important role of the GABAergic system in the oscillatory
   mechanisms was suggested by the following observations. (a) Bicuculline ,
   a GABA_A receptor antagonist, completely inhibited the oscillation induced
   by CCh. (b) Pentobarbital , which prolongs the opening time of the GABA_A
   receptor Cl^-channel, lowered the oscillation frequency (e.g., from 34Hz to
   26Hz). We conclude that the CCh-driven gamma-band oscillations are
   generated in response to the activation of muscarinic acetylcholine
   receptors, and that the GABA_A receptor-Cl^-channel complex is
   indispensable for the oscillations to occur, the oscillation frequency being
   controlled by the opening time of the Cl^- channel. Further studies of the
   CCh-driven gamma-band oscillations are being done to make clear the
   biological importance of the phenomena.

2. Inhibitory synaptic transmission and the hyperexcitability of the brain

   Inhibitory synaptic transmission is important for the control of neuronal
   excitability and alterations in the inhibitory circuits can lead to neurological
   and psychiatric disorders in humans. The El mouse is a mutant strain
   predisposed to seizures. We have previously reported a decrease in
   GABAergic function in hippocampus from El mice. The alterations of
   GABAergic function are further being studied.

3. Fiber-optic EEG and ECG monitoring instruments for use in the operating room

   We developed fiber-optic EEG and ECG monitoring instruments. The
   newly developed instruments are free from such problems as the electrical
   shock, patient burns and susceptibility to electrosurgery interference
   associated with conventional monitors. A further refinement of the fiber-
   optic monitoring system is in progress.

T. Takaki, H. Sugano, H. Tobata & T. Muteki(1987):

Fiber-optic ECG monitoring instrument for use in the operating room

Med. & Biol. Eng. & Comput., 25: 443-447

T. Takaki(1988):

EEG enhancement during electrosurgery using an optical fiber

Med. & Biol. Eng. & Comput., 26:397-403

Muneyuki, H., Ikematsu, M., Iseki, M., Sugiyama, Y., Mizukami, A., Ohno, K., Yoshida, M. and Hirata, H. (1993):

Direct transmembraneous incorporation of Bacteriorhodopsin into
Planar Phospholipid Bilayers

Biochim. Biophys. Acta 1183 :171-179.

Ohno K, and Hirata, H. (1994) :

A Proton Pump , Bacteriorhodopsin , Has a Proton Channel

Activity Which Is Gated by Light

J of UOEH 16:(1) 1-18

Kawano, H., Sashihara, S., Mita, T., Ohno, K., Kawamura, M. and Yoshii, K. (1994):

Phenytoin, an antiepileptic drug, competetively blocked non-NMDA
receptors produced by Xenopus oocytes.

Neuroscience Letters 166: 183-186

1. Koki Ohno (Ph.D.)

2. Key Words:

   Gamma-band oscillation / 40 Hz /Ach receptor / inhibitory synapse / neural network

3. Publications:

   Otomo, J., Ikegami, A., Ohno, K. and Takeuchi, Y.(1986):

   Surface charge movements of purple membrane during light-dark adaptation.

   Biophys. J. 50: 205-211.

   Hirata, H., Ohno, K., Sone, N., Kagawa, Y. and Hamamoto, T.(1986):

   Direct measurement of the electrogenicity of the H＋-ATPase from thermophilic bacterium PS3 reconstituted into planar phospholipid bilayers.

   J. Biol. Chem. 261: 9839-9843.

   Muneyuki, E., Ohno,K., Kagawa, Y. and Hirata, H.(1987):

   Reconstitution of the Proton Translocating ATPase from Bovine

   Heart Mitochondria into Planar Phospholipid Bilayer Membranes.

   J. Biochem. 102: 1433-1440.

   Muneyuki, H., Ikematsu, M., Iseki, M., Sugiyama, Y.,

   Mizukami, A., Ohno, K., Yoshida, M. and Hirata, H. (1993):

   Direct transmembraneous incorporation of Bacteriorhodopsin into Planar Phospholipid Bilayers

   Biochim. Biophys. Acta 1183 :171-179.

   Ohno K, and Hirata, H. (1994) :

   A Proton Pump , Bacteriorhodopsin , Has a Proton Channel Activity Which Is Gated by Light

   J of UOEH 16:(1) 1-18

   Kawano, H., Sashihara, S., Mita, T., Ohno, K., Kawamura, M. and Yoshii, K. (1994):

   Phenytoin, an antiepileptic drug, competetively blocked non-NMDA receptors produced by Xenopus oocytes.

   Neuroscience Letters 166: 183-186

   Ono, T., Fueta, Y., Janjua, N., Ohmori, O., Ohno, K., Murai, Y. and Mita, T. (1997):

   Granule cell disinhibition in dentate gyrus of genetically seizure susceptible El mice

   Brain Research 745:165-172

   Fueta, Y., Ohno, K. and Mita, T. (1998):

   Large frequency potentiation induced by 2 Hz stimulation in the hippocampus of epileptic El mice

   Brain Research 792:79-88

   Fueta, Y., Kawano, H., Ono, T., Mita, T., Fukata, K., and Ohno, K (1998):

   Regional differences in hippocampal excitability manifested by paired-pulse stimulation of genetically epileptic El mice

   Brain Research 779:324-328

   Fueta, Y., Schwarz, W., Takeda, K., Kawamura, M., Fukata, K., and Ohno, K. (2000):

   Effects of GABA-uptake inhibitor and GABA-transaminase inhibitor in El mice

   Control and Diseases of Sodium Dependent Transport Proteins and Ion

   Channels:383-384

   Ohno, K. and Takaki, T. (2001):

   Electrical Conductivity of Ordinary Water, as an Introduction to Experimental Physics

   ICEC NEWSLETTER on PHYSICS EDUCATION 8:12

   Fueta, Y., Schwarz, W., Ohno, K., Endo, Y. and Mita, T. (2002):

   Selective suppression of hippocampal region hyperexcitability related to seizure susceptibility in epileptic El mice by the GABA-transporter inhibitor tiagabine

   Brain Research 947(2):212-217
   

Visiting Professor

1. Toshiaki Takaki (DMSc.)

2. Key words:

   fiber-optic transmission / ECG and EEG monitoring / electrosurgical unit / interference / noise reduction

3. Publications:

   T. Takaki, H. Sugano, H. Tobata & T. Muteki

   Fiber-optic ECG monitoring instrument for use in the operating room

   Med. & Biol. Eng. & Comput., 1987, 25, 443-447

   T. Takaki

   EEG enhancement during electrosurgery using an optical fiber

   Med. & Biol. Eng. & Comput., 1988, 26, 397-403