Excitatory synaptic transmission and its modulation by PKC is unchanged in the hippocampus of GAP-43-deficient mice.
We compared excitatory synaptic transmission between hippocampal pyramidal cells in dissociated hippocampal cell cultures and in area CA3 of hippocampal slice cultures derived from wild-type mice and mice with a genetic deletion of the presynaptic growth associated protein GAP-43. The basal frequency and amplitude of action potential-dependent and -independent spontaneous excitatory postsynaptic currents were similar in both groups. The probability that any two CA3 pyramidal cells in wild-type or GAP-43 knockout (-/-) slice cultures were synaptically connected was assessed with paired recordings and was not different. Furthermore, unitary synaptic responses were similar in the two genotypes. Bath application of phorbol 12,13-diacetate (0.6-3 microM) elicited a comparable increase in the frequency of miniature excitatory synaptic currents in wild-type and GAP-43 (-/-) cultures. This effect was blocked by the protein kinase C inhibitor, bisindolylmaleimide I (1.2 microM). Finally, 3 microM phorbol 12,13-diacetate potentiated the amplitude of unitary synaptic currents to a comparable extent in wild-type and GAP-43 (-/-) slice cultures. We conclude that GAP-43 is not required for normal excitatory synaptic transmission or the potentiation of presynaptic glutamate release mediated by activation of protein kinase C in the hippocampus.
Brain Research Institute, University of Zurich, Switzerland.
M
M
Capogna
C
C
Fankhauser
V
V
Gagliardini
B H
BH
Gähwiler
S M
SM
Thompson
D000818:Animals; D017931:DNA Primers; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D019922:GAP-43 Protein / Q000235:genetics*; D017353:Gene Deletion; D005838:Genotype; D018698:Glutamic Acid / Q000378:metabolism; D006624:Hippocampus / Q000737:chemistry / Q000166:cytology / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010703:Phorbol Esters / Q000494:pharmacology; D011493:Protein Kinase C / Q000378:metabolism*; D017966:Pyramidal Cells / Q000737:chemistry / Q000201:enzymology; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*
D017931:DNA Primers; D019922:GAP-43 Protein; D010703:Phorbol Esters; D018698:Glutamic Acid; D011493:Protein Kinase C