EN
The effect of lead on GABA(b) binding was studied on membranes obtainded from acute and chronically lead-treated rats. Acute lead treatment reduced both GABA(b) affinity (K(d)) by about 30% and density of receptor (B(max)) by about 15%. On the contrary chronic lead treatment increased receptor capacity by about 20% in spite of decreased receptor affinity by 25%. Both acute and chronic lead treatment shiffted displacement curves toward higher concentration of non-labelled compound (decreased affinity). The results show that lead can affect the GABA(b) binding in two ways: by reducing affinity of binding and by altering capacity of binding.