Perfusion of immobilized isolated nerve terminals as a model for the regulation of transmitter release: release of different, endogenous transmitters, repeated stimulation, and high time resolution.
To study the release of neurotransmitters, i.e., the recruitment of transmitters for release and the regulation of the release process, isolated nerve terminals (synaptosomes) of the rat forebrain were immobilized in Sephadex gel inside a perfusion chamber. In this way, the following were achieved: (a) A very limited pressure stress was exerted on the synaptosomes, so that these remained viable for long periods (greater than 30 min) inside the chamber and did not elute from the chamber, which allowed long-term experiments with repeated stimulations; (b) estimation of the release of various endogenous transmitters, both in a Ca(2+)-dependent (exocytotic) and Ca(2+)-independent manner; (c) a step-like stimulation with depolarizing agents (rise time, 3-4 s) and a high time resolution (600-ms sampling); and (d) negligible reuptake of transmitter into the terminals or extracellular breakdown. It is concluded that this perfusion setup helps to provide new insights in the presynaptic stimulus-secretion coupling, co-transmission, and the exo-endocytosis cycle.
Department of Experimental Zoology, University of Amsterdam, The Netherlands.
M
M
Verhage
H
H
Sandman
F
F
Mosselveld
M
M
van de Velde
P A
PA
Hengst
F H
FH
Lopes da Silva
W E
WE
Ghijsen
D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000502:physiology; D004594:Electrophysiology; D007700:Kinetics; D009411:Nerve Endings / Q000378:metabolism* / Q000502:physiology; D009467:Neuromuscular Depolarizing Agents / Q000494:pharmacology; D009479:Neuropeptides / Q000378:metabolism; D018377:Neurotransmitter Agents / Q000378:metabolism*; D010477:Perfusion; D011188:Potassium / Q000502:physiology; D013574:Synaptosomes / Q000378:metabolism; D013997:Time Factors
D000596:Amino Acids; D009467:Neuromuscular Depolarizing Agents; D009479:Neuropeptides; D018377:Neurotransmitter Agents; D011188:Potassium; D002118:Calcium