12 pigs underwent the experiment. The animals were all sexually mature. In the group of the experimental animals – in 9 pigs – the experimental procedure was performed which depended on lateral or bilateral extirpation of the specific complexes of the mammary gland with leaving the skin. The remaining pigs constituted the control group. All animals were kept alive for 21 days, after which they were put to sleep and the following material was taken for further examination: the brain stem, the thoracic-lumbar-sacral part of the spinal cord with adequate nerve ganglia, sympathetic trunk ganglia and the following ganglia and plexuses of abdominal and pelvic cavity: celiac, cranial mesenteric, intermesenteric, caudal mesenteric, hypogastric and pelvic. The material was elaborated on histologically. The experiments conducted on experimental and control animals caused the occurrence of deep degenerative lesions in the nerve cells of the central and the peripheral nervous system, which gave rise to establishing of the localization of the sympathetic nerve cells innervating the mammary gland in pig. The results of the study and the localization of the retrograde changes allow stating that the sympathetic nerve cells reaching the mammary gland are of multi-source origin. They come both from the central and peripheral nervous system.

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