Myoendocrine-like cells in invertebrates: occurrence of noncardiac striated secretory-like myocytes in the gut of the ant Formica polyctena.
The occurrence of myoendocrine-like cells investing the ampullar draining region of Malpighian tubules and neighboring midgut and hindgut regions of the ant Formica polyctena is reported. These striated muscle cells show small electron-dense endocrine-like granules (130 +/- 0.95 nm) in addition to myofilaments and ordinary organules of the myocytes. Apart from their contractile function, such ultrastructural features suggest a regulatory role for these cells, as is the case of vertebrate myoendocrine cells. As far as we know, the ant secretory myocytes reported here constitute the first description of myoendocrine cells among invertebrates, as well as the first report of secretory, striated muscle cells outside the heart in the animal kingdom.
Garayoa
M
M
Department of Histology and Histopathology, University of Navarra, Pamplona, Spain.
Villaro
A C
AC
Sesma
P
P
D000818:Animals; D001000:Ants / Q000033:anatomy & histology / Q000502:physiology*; D004064:Digestive System / Q000033:anatomy & histology / Q000166:cytology; D004068:Digestive System Physiological Phenomena; D004702:Endocrine Glands / Q000033:anatomy & histology / Q000166:cytology* / Q000502:physiology; D008317:Malpighian Tubules / Q000166:cytology / Q000502:physiology / Q000648:ultrastructure; D008854:Microscopy, Electron; D009132:Muscles / Q000033:anatomy & histology / Q000166:cytology* / Q000502:physiology