Several recent investigations have shown that epithelial cells actively take part in the control of homeostasis of the skin organism. This concept is essentially based on three observations.
- Keratinocytes are able to synthesize cytokines and, thus, interfere with immunological processes.
- Keratinocytes express receptors for catecholamines (CA), which are any of the group of amines derived from catechol that have imporant physiological effects as neurotransmitters and hormones and include epinephrine, norephinephrine and dopamine.
- Keratinocytes locally synthesize CA hormones.