Ultrastructure of the Granular Glands in the Amphibian Skin

양서루 피부 과립선의 미세구조

The authors observed the ultrastructure of the granular glands in the amphibian skin with an electron microscope. The specimens from the experimental animals (Bombina orientalis, Bufo bufo gargarizans, Rana nigromaculata and Rana rugosa) were fixed in 2.5% glutaraldehyde-paraformaldehyde fixative in phosphate buffer at pH 7.2 prior to fixation in 1% osmium tetroxide, dehydrated in graded ethanol and acetone, embedded in Epon 812 mixture, and sectioned with a LKB-ultramicrotome. the ultrathin sections were contrasted with uranyl acetate and lead citrate and observed with a JEOL-100B electron microscope. The results were as follws: 1. The granular gland in the amphibian skin consisted of the glandular epithelial and the myoepithelial cells. 2. The epithelial cells of the granular gland in the amphibian skin consisted of the dark cells but the light cells were also observed in that of Bombina orientalis. 3. The granular glands of the amphibian skin were in holocrine fashion. 4. The nuclei of the epithelial cells of the amphibian cutaneous granular glands were round or oval and showed small and large inforldings of nuclear envelope. Heterochromatins were mainly distributed near the nuclear envelope. Mitochondria were mainly distributed in the perinuclear portion and rough-surfaced endoplasmic reticulums were developed in the cytoplasm but smooth-surfaced endoplasmic reticulums were not well developed. 5. Secretory granules were round or oval and electron-dense and less electron-dense granules were observed. 6. The authors infer that the differences in electron density of the secretory granules in the granular glands of the amphibian skin are due to difference in the concentrations of secretory substances as related to the processes of its formation, and that those chemical components are identical.

양서류 피부과립선의 미세구조를 관찰하기 위하여 무미양서류인 무당개구리(Bombina orientalis), 두꺼비 (Bufo bufo gargarizans), 개구리 (Rana nigromaculata) 및 옴개구리 (Rana rugosa)의 피부조직은 2.5% glutaraldehyde-paraformaldehyde (pH 7.2)와 1%osmium tetroxide에 전후 고정한 후 ethanol과 acetone으로 탈수, Epon 812 mixture에 포매하여 LKB ultramicrotome으로 초박절표본을 만들어 uranyl acetate와 lead citrate으로 염색하여 JEOL-100B형 전자현미경으로 관찰하여 다음과 같은 결과를 얻었다. 1. 양서류 피부과립선은 선상피세포와 근상피세포로 이루어졌다. 2. 양서류 피부과립선의 선상피세포는 암세포들로 구성되었으나 무당개구리에서는 명세포도 관찰되었다. 3. 양서류 피부과립선은 전분지를 하였다. 4. 양서류 피부과립선 상피세포의 핵은 원형 내지 타원형으로 크고 작은 핵경함요를 보였고, heterochromatin은 주로 핵경 인접부에 많았다. 세포질에는 mitochondria가 핵주변부에 비교적 많이 산재하였고, rough-surfaced endoplasmic reticulum은 핵 주변부에 발달하였지만 smooth-surfaced endoplasmic reticulum은 미약하였다. 5. 분비과립들은 구형 또는 난형으로 높은 전자밀도를 보였으며 다소 약한 전자밀도를 보이는 과립도 관찰되었다. 6. 양서류 과립선내 분비과립들이 같은 세포내에서 다소 전자밀도의 차이를 보이는 것은 분비과립의 형성단계에 따른 농도 차이에 기인하며 그 화학적 조성은 유사하다고 생각된다.