High CO2-bicarbonate buffer modifies GABAergic inhibitory effect at the crayfish neuromuscular synapse.
gamma-Aminobutyric acid (GABA) activated channels have a considerable permeability to bicarbonate ions (HCO3-), which might alter the efficacy of chloride-dependent synaptic inhibition. Saturation of the bicarbonate-buffered physiologic solution with 15% CO2/85% O2 increased the depolarizing inhibitory postsynaptic potential (IPSP) amplitude in crayfish muscle by 290% due to a shift of +8.33 mV in its reversal potential. Consequently, the normal inhibition exerted by the IPSP on the excitatory postsynaptic potential is reversed to large excitation.
Golan
H
H
Department of Physiology, Faculty of Health Sciences, Ben Gurion University of the Negev, Beer-Sheva, Israel.
Barkai
E
E
Grossman
Y
Y
D000818:Animals; D003400:Astacoidea; D001639:Bicarbonates / Q000494:pharmacology*; D002021:Buffers; D002245:Carbon Dioxide / Q000494:pharmacology*; D005071:Evoked Potentials / Q000187:drug effects; D066298:In Vitro Techniques; D009469:Neuromuscular Junction / Q000187:drug effects / Q000502:physiology*; D011963:Receptors, GABA-A / Q000502:physiology; D013569:Synapses / Q000187:drug effects / Q000502:physiology*; D013997:Time Factors; D005680:gamma-Aminobutyric Acid / Q000502:physiology*
D001639:Bicarbonates; D002021:Buffers; D011963:Receptors, GABA-A; D002245:Carbon Dioxide; D005680:gamma-Aminobutyric Acid