title: Ultrastructure of the pineal gland of the brush mouse (Peromyscus boylei): influence of long and short photoperiod.
abstract: The ultrastructure of the pineal gland of wild-captured brush mice (Peromyscus boylei) was examined. A homogeneous population of pinealocytes was present in the pineal gland of this species. The Golgi apparatus, granular endoplasmic reticulum, mitochondria, lysosomes, dense-core vesicles, vacuoles containing fluocculent material, clear vesicles, microtubules and glycogen particles were consistent components of the pinealocyte cytoplasm; infrequently-observed organelles included centrioles, "synaptic" ribbons, subsurface cisternae, multivesicular bodies, lipid droplets and annulate lamellae-like structures. Quantitative comparison of pinealocyte ultrastructure revealed larger cross-sectional areas of cytoplasma, nucleus, Golgi apparatus, granular endoplasmic reticulum, mitochondria and vacuoles containing flocculent material as well as higher number of dense-core vesicles in the animals kept in short photoperiod (LD 8 : 16) as compared to those in animals kept in long photoperiod (LD 16 : 8). These observations suggest that restricting the amount of light to which animals are exposed activated the pinealocytes of brush mice.
mesh_terms: D000818:Animals; D005260:Female; D008027:Light; D008297:Male; D008854:Microscopy, Electron; D009412:Nerve Fibers / Q000648:ultrastructure; D009474:Neurons / Q000648:ultrastructure; D009940:Organoids / Q000648:ultrastructure; D010542:Peromyscus / Q000033:anatomy & histology*; D010870:Pineal Gland / Q000033:anatomy & histology*