Bicuculline increases the intracellular calcium response of CA1 hippocampal neurons to synaptic stimulation.
Intracellular calcium levels were measured by ratio imaging of Fura-2-injected CA1 pyramidal neurons during repetitive electrical stimulation of the Schaffer collaterals in rat hippocampal slices. Baseline intracellular calcium levels of 102 nM increased to 190 nM during a 3-s stimulus train of 5 Hz. Bicuculline (20 microM) significantly enhanced this stimulus-dependent rise in intracellular calcium, while the baseline calcium levels remained unchanged. Concomitantly performed extra- and intracellular electrophysiological recordings indicate that the increased calcium response in the presence of bicuculline is linked to a prolongation of the excitatory postsynaptic potential and the induction of multiple action potentials. The bicuculline-induced increased calcium response could have long-term implications for cell function and eventually lead to cell degeneration.
Department of Experimental Zoology, University of Amsterdam, The Netherlands.
J A
JA
van der Linden
M
M
Joëls
H
H
Karst
A J
AJ
Juta
W J
WJ
Wadman
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000818:Animals; D001640:Bicuculline / Q000494:pharmacology*; D002118:Calcium / Q000494:pharmacology*; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology; D004558:Electric Stimulation; D006624:Hippocampus / Q000187:drug effects* / Q000502:physiology; D015640:Ion Channel Gating / Q000187:drug effects*; D008297:Male; D009474:Neurons / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D011963:Receptors, GABA-A / Q000187:drug effects / Q000502:physiology*; D017470:Receptors, Glutamate / Q000187:drug effects / Q000502:physiology*; D013569:Synapses / Q000502:physiology
D015220:Calcium Channels; D011963:Receptors, GABA-A; D017470:Receptors, Glutamate; D002118:Calcium; D001640:Bicuculline