Presynaptic Mechanism of Action Induced by 5-HT in Nerve Terminals: Possible Involvement of Ryanodine and IP3 Sensitive Ca2+ StoresComparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology (2005)
AbstractAlthough modulation of transmitter release by serotonin (5-HT) at crayfish neuromuscular junctions has been known since 1965, the mechanisms of action have not been established in this classical synaptic preparation. We show that injections of adenophostin-A (an IP3 analog) in the nerve terminals greatly enhances synaptic transmission. Exposure to ryanodine (Ry) produces a biphasic response: at low concentration it is excitatory and high concentration it is inhibitory. Likewise, a low concentration (1 μM) of caffeine enhances synaptic transmission, whereas a high concentration (10 mM) has little effect on transmission. The varied responses and sensitivity to Ry and caffeine suggest a Ca2+-induced Ca2+-release mechanism and/or the presence of an IP3-receptor within the terminal. Thus, it is likely 5-HT's response is due to activation of intracellular pathways, which subsequently release Ca2+ from internal stores.
Publication DateNovember, 2005
Citation InformationAmanda J. Dropic, Eugen Brailoiu and Robin L Cooper. "Presynaptic Mechanism of Action Induced by 5-HT in Nerve Terminals: Possible Involvement of Ryanodine and IP3 Sensitive Ca2+ Stores" Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology Vol. 142 Iss. 3 (2005)
Available at: http://works.bepress.com/robin_cooper/21/