Probabilistic secretion of quanta from the release sites of nerve terminals in amphibian muscle modulated by seasonal changes.
The number of quanta secreted from release sites along visualized terminal branches at toad (Bufo marinus) neuromuscular junctions during different seasons was determined. Terminal branches were visualized by prior staining with the fluorescent dye, 3,3'-diethyloxadicarbocyanine iodide (DiOC2(5)). The average number of quanta secreted by release sites and recorded with an extracellular electrode was determined at different positions along terminal branches in winter and summer. There was a decrease in me at different positions along terminal branches in winter compared with me at similar positions in summer during each of 3 years. The observations show that the capacity of release sites to secrete quanta is modulated by seasonal changes.
Bennett
M R
MR
Department of Physiology, University of Sydney, Australia.
Lavidis
N A
NA
D000818:Animals; D002024:Bufo marinus / Q000502:physiology; D015220:Calcium Channels / Q000502:physiology; D008839:Microelectrodes; D009132:Muscles / Q000294:innervation; D009411:Nerve Endings / Q000378:metabolism*; D009469:Neuromuscular Junction / Q000378:metabolism*; D018377:Neurotransmitter Agents / Q000378:metabolism*; D012621:Seasons; D012636:Secretory Rate
D015220:Calcium Channels; D018377:Neurotransmitter Agents