Differences between the classical synaptic and the nonsynaptic interaction1-a
| Synaptic | Nonsynaptic | |
|---|---|---|
| Type of communication | One-to-one | One-to-many |
| Delay | Short (100–200 msec) | Long (>1 s) |
| Action (duration) | Short (msec) and phasic | Long (min) and tonic |
| Discrimination | Dependence of the presence of receptors | |
| Sensitivity of receptors | Low affinity | High affinity1-b |
| Agonist concentration in the vicinity of receptors | mM | nM–μM |
| Chemical agent has to | Cross the gap (5–20 nm) | Diffuse distances of some micrometers |
| Morphological characteristics of presynaptic modulation | Axo-axonic synapse (post-junctional specializations) | Free nerve endings, varicosities (no post-junctional specializations) mismatch of release site/receptor |