BINDING OF [H-3] BATRACHOTOXININ A-20-ALPHA-BENZOATE AND [H-3] SAXITOXIN TO RECEPTOR-SITES ASSOCIATED WITH SODIUM-CHANNELS IN TROUT BRAIN SYNAPTONEUROSOMES
Rubin, JG; Soderlund, DM
| HERO ID | 2796993 |
|---|---|
| In Press | No |
| Year | 1993 |
| Title | BINDING OF [H-3] BATRACHOTOXININ A-20-ALPHA-BENZOATE AND [H-3] SAXITOXIN TO RECEPTOR-SITES ASSOCIATED WITH SODIUM-CHANNELS IN TROUT BRAIN SYNAPTONEUROSOMES |
| Authors | Rubin, JG; Soderlund, DM |
| Journal | Comparative Biochemistry and Physiology - Part C: Comparative Pharmacology and Toxicology |
| Volume | 105 |
| Issue | 2 |
| Page Numbers | 231-238 |
| Abstract | 1. [3H]Batrachotoxinin A-20-alpha-benzoate ([3H]BTX-B) and [3H]saxitoxin ([3H]STX), radioligands that bind to distinct sites on the voltage-sensitive sodium channel, were bound specifically to saturable sites in rainbow trout (Oncorhynchus mykiss) brain synaptoneurosomes. 2. Specific [3H]BTX-B binding was temperature dependent with highest levels of specific [3H]BTX-B binding observed at 7 degrees C. Specific binding was inversely correlated with assay temperature at temperatures above 7 degrees C. 3. Saturating concentrations of scorpion (Leiurus quinquestriatus) venom (ScV) stimulated specific [3H]BTX-B binding at 27 degrees C, but not at 7 degrees C. The dihydropyrazole insecticide RH 3421 inhibited specific [3H]BTX-B binding at 7 degrees C but had no effect on specific binding at 27 degrees C. The sodium channel activators veratridine and aconitine and the local anesthetic dibucaine inhibited specific [3H]BTX-B binding at both 7 degrees C and 27 degrees C. 4. Displacement experiments in the presence of ScV at 27 degrees C gave an equilibrium dissociation constant (KD) for [3H]BTX-B of 710 nM and a maximal binding capacity (Bmax) of 11.3 pmol/mg protein. Kinetic experiments established the rates of association (1.17 x 10(5) min-1 nM-1) and dissociation (0.0514 min-1) of the ligand-receptor complex. 5. The binding of [3H]STX reached apparent saturation at 7.5 nM. Scatchard analysis of the saturation data indicated a KD of 3.8 nM and a Bmax of 1.9 pmol/mg protein. 6. These studies provide evidence for high affinity, saturable binding sites for [3H]BTX-B and [3H]STX in trout brain preparations. Whereas certain neurotoxins modified the specific binding of [3H]BTX-B in trout brain synaptoneurosomes in a predictable fashion, other compounds known to affect specific [3H]BTX-B binding in mammalian brain preparations had no effect on specific [3H]BTX-B binding in the trout. |
| Doi | 10.1016/0742-8413(93)90200-5 |
| Pmid | 8103729 |
| Wosid | WOS:A1993LN38800016 |
| Is Certified Translation | No |
| Dupe Override | No |
| Is Public | Yes |
| Language Text | English |