Scanning Electron Microscopy of the Superficial Pineal Gland of the 15‐day‐old rat (Rattus norvegicus)

Abstract

The presence of a cortex and medulla in the superficial pineal gland has been a controversial point in the morphology of this structure in mammals. The published reports indicate contradictory data especially in rodents. In this study the pineal gland of 15-day-old male rats (Rattus norvegicus) were studied, using scanning electron microscopy, in an attempt to determine whether or not a cortex and medulla are apparent in the pineal gland of young rats. The superficial pineal gland of the 15-day-old rat exhibited both a cortex and a medulla; these areas exhibited different structural organizations. The cortex had a thickness of 40-80 microm and the cells did not show a particular arrangement. The center of the gland was composed of a medulla, which had a width of 1000-1200 microm, and consisted of cells arranged in cords; its morphology was distinctly different from that of the cortex.

The morphology of the pineal gland of the yellow‐toothed cavy (Galea Spixii Wagler, 1831) and red‐rumped agouti (Dasyprocta leporina linnaeus, 1758)

“…It was classified as pear‐shaped, divided into apex, body, and base. Employing SEM technique, Ortiz et al () verified that the surface of the pineal gland of the Rattus norvegicus had two lobules separated by a furrow in the middle of the gland, differing from that reported for the agouti and cavy.…”

Gross and Microscopic Anatomy of the Pineal Gland in Nasua nasua– Coati (Linnaeus, 1766)

“…According to Ortiz et al., 2004, the pineal gland of some rodents ( Rattus norvegicus ) exhibits both cortex and medulla. Using SEM, these distinct structures were not found in the pineal gland of the coati, which suggests the pineal parenchyma of the coati to be homogeneous in relation to its cellular composition.…”