Presynaptic mechanism of action induced by 5-HT in nerve terminals: Possible involvement of ryanodine and IP3 sensitive Ca2+ stores

Amanda J. Dropic; Eugen Brailoiu; Robin L. Cooper

doi:10.1016/j.cbpa.2005.08.025

Presynaptic mechanism of action induced by 5-HT in nerve terminals: Possible involvement of ryanodine and IP₃ sensitive Ca²⁺ stores

Amanda J. Dropic, Eugen Brailoiu, Robin L. Cooper

Research output: Contribution to journal › Article › peer-review

23 Scopus citations

Abstract

Although 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.

Original language	English
Pages (from-to)	355-361
Number of pages	7
Journal	Comparative Biochemistry and Physiology - A Molecular and Integrative Physiology
Volume	142
Issue number	3
DOIs	https://doi.org/10.1016/j.cbpa.2005.08.025
State	Published - Nov 2005

Bibliographical note

Funding Information:
We thank Dr. M. Miyamoto at East TN State for critical editorial comments on the manuscript. Funding was provided by NSF grants IBN-9808631 and IBN-0131459 (RLC) and an undergraduate training fellowship by G. Ribble in the School of Biological Sciences at the University of Kentucky (AJF). Dropic's maiden name at time of research was Fox.

Keywords

Crayfish
Neuromodulation
Presynaptic
Serotonin
Synapse

ASJC Scopus subject areas

Biochemistry
Physiology
Molecular Biology

Access to Document

10.1016/j.cbpa.2005.08.025

Cite this

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title = "Presynaptic mechanism of action induced by 5-HT in nerve terminals: Possible involvement of ryanodine and IP3 sensitive Ca2+ stores",

abstract = "Although 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.",

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Presynaptic mechanism of action induced by 5-HT in nerve terminals: Possible involvement of ryanodine and IP₃ sensitive Ca²⁺ stores. / Dropic, Amanda J.; Brailoiu, Eugen; Cooper, Robin L.
In: Comparative Biochemistry and Physiology - A Molecular and Integrative Physiology, Vol. 142, No. 3, 11.2005, p. 355-361.

Research output: Contribution to journal › Article › peer-review

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