2-Amino-3-phosphonopropionate fails to block postsynaptic effects of metabotropic glutamate receptors in rat hippocampal neurones.
Metabotropic glutamate receptors (mGluRs) operate via the phosphoinositide second messenger cascade and have various modulatory effects on central neurones. 2-Amino-3-phosphonopropionate (AP3) has been proposed as a selective antagonist of mGluR and used to explore the physiological functions of mGluR. We have compared the effects of mGluR agonists in the presence and absence of AP3 using intracellular recording from CA1 pyramidal neurones in rat hippocampal slices. Two mM D,L-AP3 or 1 mM L-AP3 did not cause any detectable change in the effects of mGluR agonists trans-1-amino-cyclopentyl-1,3-dicarboxylate (t-ACPD) or quisqualate. These agonists still induced depolarization, inhibition of the slow after-hyperpolarization and slowing of the spike repolarization. The results argue against AP3 being an antagonist of postsynaptic mGluRs.
Hu
G Y
GY
Institute of Neurophysiology, University of Oslo, Norway.
Storm
J F
JF
D000200:Action Potentials / Q000187:drug effects; D000409:Alanine / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D003515:Cycloleucine / Q000031:analogs & derivatives / Q000494:pharmacology; D005260:Female; D005971:Glutamates; D006624:Hippocampus / Q000187:drug effects* / Q000502:physiology; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D009474:Neurons / Q000187:drug effects* / Q000502:physiology; D009498:Neurotoxins; D016318:Quisqualic Acid / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D017470:Receptors, Glutamate; D017981:Receptors, Neurotransmitter / Q000037:antagonists & inhibitors*
D005971:Glutamates; D009498:Neurotoxins; D017470:Receptors, Glutamate; D017981:Receptors, Neurotransmitter; C000211:2-amino-3-phosphonopropionic acid; D003515:Cycloleucine; C036361:1-amino-1,3-dicarboxycyclopentane; D016318:Quisqualic Acid; D000409:Alanine