Premium
Metabotropic glutamate receptors modulate [ 3 H]acetylcholine release from cultured amacrine‐like neurons
Author(s) -
Caramelo Olga L.,
Santos Paulo F.,
Carvalho Arsélio P.,
Duarte Carlos B.
Publication year - 1999
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/(sici)1097-4547(19991115)58:4<505::aid-jnr4>3.0.co;2-j
Subject(s) - metabotropic glutamate receptor , acetylcholine , metabotropic receptor , chemistry , glutamate receptor , agonist , muscarinic acetylcholine receptor , pharmacology , biology , receptor , biochemistry
Retinal amacrine cells express metabotropic glutamate receptors (mGluRs), but their physiological role is unknown. We investigated the effect of mGluR on [ 3 H]acetylcholine release ([ 3 H]ACh) from cultured chick amacrine‐like neurons. Activation of group III mGluR with the agonist L(+)‐2‐amino‐4‐phosphonobutyric acid (L‐AP4) inhibited [ 3 H]ACh release evoked by 25 mM KCl in a dose‐dependent manner, and this effect was sensitive to pertussis toxin. In contrast, activation of group I or II mGluR with (S)‐3,5‐dihydroxyphenylglycine (DHPG) and (2S,2′R,3′R)‐2‐(2′,3′‐dicarboxycyclopropyl)glycine (DCG‐IV), respectively, did not affect significantly [ 3 H]ACh release. The effect of L‐AP4 on [ 3 H]ACh release was sensitive to nitrendipine, suggesting that it is, at least in part, due to inhibition of L‐type Ca 2+ channels. Activation of group III mGluR also partly inhibited ω‐conotoxin GVIA‐sensitive Ca 2+ channels, coupled to [ 3 H]ACh release. The L‐AP4 did not affect the cAMP levels measured in amacrine‐like neurons depolarized with 25 mM KCl or stimulated with forskolin, indicating that the effect of group III mGluR on [ 3 H]ACh release is not due to inhibition of adenylyl cyclase activity. Inhibition of protein kinase A with KT‐5720 was without effect on [ 3 H]ACh release evoked by 25 mM KCl, further indicating that the effect of group III mGluR on [ 3 H]ACh release cannot be attributed to the inhibition of the kinase. The effect of L‐AP4 on [ 3 H]ACh release was reversed by DHPG or by DCG‐IV, and activation of group II mGluR also partially inhibited cAMP production stimulated by forskolin. Taken together, our results show that the effect of group III mGluR on [ 3 H]ACh release may be due to a direct inhibition of L‐ and N‐type Ca 2+ channels and is modulated by group I and group II mGluR. J. Neurosci. Res. 58:505–514, 1999. © 1999 Wiley‐Liss, Inc.