title: Excitatory neurotoxic properties of pontamine sky blue make it a useful tool for examining the functions of focal brain parts.
abstract: Pontamine sky blue (PSB) is used in brain studies to mark the position of microelectrode and micropipette tips. However, few studies have been made on the effects of PSB on neurons; therefore we examined these effects. When puffed on isolated sensory ganglion cells of rats, PSB increased membrane conductance, depolarized membrane potential, and reduced the amplitude of action potentials. When dripped on frog sympathetic ganglion, much like hexamethonium, PSB decreased the amplitude of compound action potentials of the postganglionic strand. A bath application of PSB to sartorius muscle fibers that had been treated with tetrodotoxin depolarized the membrane potential and increased the frequency and amplitude of miniature end-plate potentials. All these effects were reversible. When injected into the rat's pontine part corresponding to the location of the canine pontine defecation reflex center, PSB produced repetitive colorectal contractions and irreversibly abolished them in response to anal-canal stimulation. The excitatory and blocking effects of PSB and its staining ability make it a useful tool for examining the functions of focal brain parts.
authors.affiliation: Department of Biologic and Materials Sciences, School of Dentistry, University of Michigan, USA.
authors.forename: Mayuko
authors.initials: M
authors.lastname: Nagano
authors.forename: Noriko
authors.initials: N
authors.lastname: Ashidate
authors.forename: Kayo
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Yohko
authors.initials: Y
authors.lastname: Ishimizu
authors.forename: Sanae
authors.initials: S
authors.lastname: Saitoh
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Konishi
authors.forename: Tomoshige
authors.initials: T
authors.lastname: Koga
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Fukuda
mesh_terms: D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000818:Animals; D001391:Azo Compounds / Q000494:pharmacology*; D001921:Brain / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D002478:Cells, Cultured; D003672:Defecation / Q000187:drug effects / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D005728:Ganglia, Sympathetic / Q000187:drug effects* / Q000502:physiology; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000502:physiology; D009474:Neurons / Q000187:drug effects* / Q000502:physiology; D009498:Neurotoxins / Q000494:pharmacology*; D011894:Rana pipiens; D051381:Rats; D017207:Rats, Sprague-Dawley; D013194:Staining and Labeling / Q000379:methods; D009435:Synaptic Transmission / Q000187:drug effects* / Q000502:physiology; D014343:Trypan Blue
chemical_list: D001391:Azo Compounds; D009498:Neurotoxins; C009000:pontamine sky blue; D014343:Trypan Blue