Catecholamine-storing cells at acupuncture points of rabbits

Recent studies have shown that specific sites of the skin related to the acupoints contain a high concentration of catecholamines, especially noradrenaline (NA). Considering this newly discovered property of the acupoints we assumed that heterogeneous distribution of cutaneous catecholamines could be associated with a specific location of catecholamine-storing cells in acupoint sites. In the present work we used an immunohistochemical method and confocal laser scanning microscopy to examine the presence of catecholamine-storing cells at acupoints of rabbits. Double immunofluorescence staining with antibodies against adrenaline and NA revealed only the cells storing NA in the dermal layer of rabbit skin. NA-storing cells were randomly scattered as single cells as well as existing in small clusters in a globular tissue formation surrounded by blood vessels and capillaries. Microscopic analysis of histological sections also revealed that the distribution of NA-storing cells was closely associated with the location of acupoints. Thus results from our study strongly suggest that acupoint areas of rabbit skin contain catecholamine-storing cells which can release a high level of NA during acupuncture stimulation.