Table 1.
Summary of proposed model for nAChR expression in embryonic chick neurones during development
| Relative abundance | Pharmacology - relative sensitivity to | Deletion by AS | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Proposed composition | 1,2γ (pS) | 1,2Open duration (ms) | 1 Early | 2 Int | 1 Late | 1,2†ACh | 2 Cyt | 1n-BgTx | 2,3α-BgTx | 2 MLA | 2α3 | 2α5 | 2α7 | Prior name |
| (α3)2(βx)3 | ≈15 | ≈1 & 5 | +++(+) | +++ | – | ++++ | + | + | – | – | y | n | n | S10 |
| (α3)1(α7)1(βx)3 | ≈18-22 | ≈1 & 5 | – | + | ++ | +++ | – | + | + | – | y | n | y | S17 |
| (α3)3(βx)2 | ≈25-30 | ≈1 & 7 | +++ | ++ | – | ++++ | + | + | – | – | y | n | n | M10 |
| (α3)1(α5)1(α7)1(βx)2 | ≈35 | ≈1 & 7 | – | ++++ | ++++ | ++ | – | + | -/?+ | + | y | y | y | M17 |
| (α3)2(α5)2(βx)1 | ≈50 | ≈3 | + | ++(+) | * | + | + | + | – | – | y | y | n | L10 |
| (α3)1(α5)2(α7)1(βx)1 | ≈50* | ≈20 | – | ++ | +++ | + | – | + | ?/− | ? | y | y | y | L17* |
| ? | 65 | – | (+) | (+) | + | ? | + | ? | ? | y | ? | ? | XI | |
References:
2
This and accompanying paper, Yu & Role (1998)
*
Note that our previous nomenclature did not distinguish between slow and fast 50 pS channels, i.e. both were designated L17 in ED17 neurones so that the relative abundance of ‘L17′ refers to both kinetic classes.
†
The number of +s indicated represent the proposed apparent affinity for ACh with +++ indicating higher affinity than +. The stages of neuronal development are referred to as early (embryonic days (E) 8-10), intermediate (Int, E11-14) and late (> E17). Abbreviations: y, yes; n, no.