start-ver=1.4
cd-journal=joma
no-vol=1808
cd-vols=
no-issue=1
article-no=
start-page=490
end-page=497
dt-received=
dt-revised=
dt-accepted=
dt-pub-year=2011
dt-pub=201101
dt-online=
en-article=
kn-article=
en-subject=
kn-subject=
en-title=
kn-title=Comparative study of the membrane-permeabilizing activities of mastoparans and related histamine-releasing agents in bacteria, erythrocytes, and mast cells
en-subtitle=
kn-subtitle=
en-abstract=
kn-abstract=The membrane-permeabilizing activities of mastoparans and related histamine-releasing agents were compared through measurements of K(+) efflux from bacteria, erythrocytes, and mast cells. Changes in bacterial cell viability, hemolysis, and histamine release, as well as in the shape of erythrocytes were also investigated. The compounds tested were mastoparans (HR1, a mastoparan from Polistes jadwagae, and a mastoparan from Vespula lewisii), granuliberin R, mast cell-degranulating peptide, and compound 48/80, as well as antimicrobial peptides, such as magainin I, magainin II, gramicidin S. and melittin. We used a K(+)-selective electrode to determine changes in the permeability to K(+) of the cytoplasmic membranes of cells. Consistent with the surface of mast cells becoming negatively charged during histamine release, due to the translocation of phosphatidylserine to the outer leaflet of the cytoplasmic membrane, histamine-releasing agents induced K(+) efflux from mast cells, dependent on their ability to increase the permeability of bacterial cytoplasmic membranes rich in negatively charged phospholipids. The present results demonstrated that amphiphilic peptides, possessing both histamine-releasing and antimicrobial capabilities, induced the permeabilization of the cytoplasmic membranes of not only bacteria but mast cells. Mastoparans increased the permeability of membranes in human erythrocytes at higher concentrations, and changed the normal discoid shape to a crenated form. The structural requirement for making the crenated form was determined using compound 48/80 and its constituents (monomer, dimer, and trimer), changing systematically the number of cationic charges of the molecules.
en-copyright=
kn-copyright=

en-aut-name=NakaoSatoshi
en-aut-sei=Nakao
en-aut-mei=Satoshi
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=1
ORCID=

en-aut-name=KomagoeKeiko
en-aut-sei=Komagoe
en-aut-mei=Keiko
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=2
ORCID=

en-aut-name=InoueTsuyoshi
en-aut-sei=Inoue
en-aut-mei=Tsuyoshi
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=3
ORCID=

en-aut-name=KatsuTakashi
en-aut-sei=Katsu
en-aut-mei=Takashi
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=4
ORCID=

affil-num=1
en-affil=
kn-affil=Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University

affil-num=2
en-affil=
kn-affil=Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University

affil-num=3
en-affil=
kn-affil=Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University

affil-num=4
en-affil=
kn-affil=Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University
en-keyword=Mastoparan
kn-keyword=Mastoparan
en-keyword=Compound 48/80
kn-keyword=Compound 48/80
en-keyword=Antimicrobial peptide
kn-keyword=Antimicrobial peptide
en-keyword=Histamine-releasing agent
kn-keyword=Histamine-releasing agent
en-keyword=Membrane permeability
kn-keyword=Membrane permeability
en-keyword=Cell shape
kn-keyword=Cell shape
END

start-ver=1.4
cd-journal=joma
no-vol=19
cd-vols=
no-issue=
article-no=
start-page=1551700
end-page=
dt-received=
dt-revised=
dt-accepted=
dt-pub-year=2025
dt-pub=20250305
dt-online=
en-article=
kn-article=
en-subject=
kn-subject=
en-title=
kn-title=Acetoacetate, a ketone body, attenuates neuronal bursts in acutely-induced epileptiform slices of the mouse hippocampus
en-subtitle=
kn-subtitle=
en-abstract=
kn-abstract=The ketogenic diet increases ketone bodies (beta-hydroxybutyrate and acetoacetate) in the brain, and ameliorates epileptic seizures in vivo. However, ketone bodies exert weak or no effects on electrical activity in rodent hippocampal slices. Especially, it remains unclear what kinds of conditions are required to strengthen the actions of ketone bodies in hippocampal slices. In the present study, we examined the effects of acetoacetate on hippocampal pyramidal cells in normal slices and epileptiform slices of mice. By using patch-clamp recordings from CA1 pyramidal cells, we first confirmed that acetoacetate did not change the membrane potentials and intrinsic properties of pyramidal cells in normal slices. However, we found that acetoacetate weakened spontaneous epileptiform bursts in pyramidal cells of epileptiform slices, which were acutely induced by applying convulsants to normal slices. Interestingly, acetoacetate did not change the frequency of the epileptiform bursts, but attenuated individual epileptiform bursts. We finally examined the effects of acetoacetate on excitatory synaptic barrages during epileptiform activity, and found that acetoacetate weakened epileptiform bursts by reducing synchronous synaptic inputs. These results show that acetoacetate attenuated neuronal bursts in epileptiform slices, but did not affect neuronal activity in normal slices, which leads to seizure-selective actions of ketone bodies.
en-copyright=
kn-copyright=

en-aut-name=WenHao
en-aut-sei=Wen
en-aut-mei=Hao
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=1
ORCID=

en-aut-name=SadaNagisa
en-aut-sei=Sada
en-aut-mei=Nagisa
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=2
ORCID=

en-aut-name=InoueTsuyoshi
en-aut-sei=Inoue
en-aut-mei=Tsuyoshi
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=3
ORCID=

affil-num=1
en-affil=Department of Biophysical Chemistry, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University
kn-affil=

affil-num=2
en-affil=Department of Biophysical Chemistry, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University
kn-affil=

affil-num=3
en-affil=Department of Biophysical Chemistry, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University
kn-affil=
en-keyword=epilepsy
kn-keyword=epilepsy
en-keyword=ketone body
kn-keyword=ketone body
en-keyword=ketogenic diet
kn-keyword=ketogenic diet
en-keyword=hippocampus
kn-keyword=hippocampus
en-keyword=slice physiology
kn-keyword=slice physiology
en-keyword=patch-clamp recording
kn-keyword=patch-clamp recording
END