title: The action of thallium acetate on spontaneous transmitter release in the rat neuromuscular junction.
abstract: Frequencies and amplitudes of miniature endplate potentials (MEPP's) were recorded from neuromuscular junctions of the rat phrenic nerve-diaphragm preparation in vitro. Superfusion of the preparations with Ringer solution containing thallium acetate (Tlac) gradually increased the frequency of MEPP's by a factor of 10 within 30 min (1 X 10(-3) mol/l Tlac) and 180 min (5 X 10(-4) mol/l Tlac), whereas the amplitude of MEPP's remained unchanged. Frequency of MEPP's fitted a Poisson-distribution which persisted during superfusion with Tl+-Ringer. Sub-MEPP amplitudes remained unaffected by the action of thallium. It is concluded that thallium interferes presynaptically with spontaneous transmitter release.
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D066298:In Vitro Techniques; D008274:Magnesium / Q000494:pharmacology; D009469:Neuromuscular Junction / Q000187:drug effects* / Q000502:physiology; D018377:Neurotransmitter Agents / Q000378:metabolism*; D009942:Organometallic Compounds; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D013793:Thallium / Q000633:toxicity*
chemical_list: D018377:Neurotransmitter Agents; D009942:Organometallic Compounds; D013793:Thallium; D008274:Magnesium; C026995:thallium acetate; D011188:Potassium