title: A combined high-voltage and scanning electron microscopic study of two types of sensory cells dissociated from the gastrodermis of Hydra.
abstract: Sensory cells dissociated from gastrodermis of Hydra were studied using high-voltage electron microscopy (HVEM) for visualization of internal features and scanning electron microscopy (SEM) to clarify surface details. HVEM revealed whole cell morphology, nuclear shape and location, apical ciliary-microvillar organization, length of microtubule bundles, and distribution of dense-cored vesicles in axonal processes and nerve terminals. SEM of the same cells revealed surface blebs and membrane perforations not easily recognized by HVEM alone. Hence, mapping of SEM surface structures can be used to determine what is surface versus interior structures in the HVEM image and thus aid in interpreting such images. The maceration procedure revealed a previously undescribed, pyriform-shaped sensory cell with oppositely-directed basal processes. This combined HVEM-SEM study of whole cells provided evidence of possible synaptic loci in an axon terminal and demonstrated a new morphological type of gastrodermal sensory cell in Hydra. These early-evolved sensory cells appear to be sensory-motor with neurosecretory granules.
authors.affiliation: Department of Anatomy and Physiology, Veterinary Medical Science Kansas State University, Manhattan.
authors.forename: J A
authors.initials: JA
authors.lastname: Westfall
authors.forename: R A
authors.initials: RA
authors.lastname: Rogers
mesh_terms: D000818:Animals; D006829:Hydra / Q000166:cytology*; D008854:Microscopy, Electron / Q000379:methods; D008855:Microscopy, Electron, Scanning / Q000379:methods; D009474:Neurons / Q000648:ultrastructure; D012679:Sense Organs / Q000166:cytology* / Q000648:ultrastructure; D013270:Stomach / Q000166:cytology* / Q000648:ultrastructure