Muscarinic cholinergic receptors on skin fibroblasts in familial affective disorder.

Cultured human skin fibroblasts possess muscarinic receptors with the properties of specific binding, saturability, pharmacologic specificity, inhibition of norepinephrine-stimulated adenylate cyclase, and increased binding after incubation with an antagonist. The number of binding sites appears to be a stable characteristic of each cell line. We studied fibroblasts from 18 patients with a major affective disorder and found that they had a higher density of binding sites than cells from 12 normal controls. Fibroblasts from 18 relatives who had histories of major or minor affective disorder also had a higher density, and those from five normal relatives were similar to controls. These results, although still preliminary, suggest that increased cholinergic-receptor density may be associated with vulnerability to affective disorders in some familial cases.