ABSTRACT
Objective To understand the distribution of nerve fibers and the types of neural cells in Aspidogaster conchiola. Methods Whole worms were subjected to silver staining, histochemical staining and hematoxylin-eosin (HE) staining, and the nervous systems of the worms were observed. Results There were 3 types of neural cells in the worm head near the cerebral ganglion, including unipolar, bipolar and multipolar neurons, which were divided into 7 types according to the morphology. There was a nerve network on the surface of pharynx and intestinal tract, as well as the reproductive organ, including testis, ovary, lower uterus and penis sac. The nerve network was consisted of circular and longitudinal nerve fibers, and the structure of the nerve network around the mouth was similar to central nerve. Conclusions The structure of the A. conchiola central nervous system is very complicated, and the neural networks may be associated with the physiologic activity of the worm. Different neural cells may have diverse functions.
ABSTRACT
Investigation of pain requires measurements of nociceptive sensitivity and other pain-related behaviors. Recent studies have indicated the superiority of gait analysis over traditional evaluations (e.g., skin sensitivity and sciatic function index [SFI]) in detecting subtle improvements and deteriorations in animal models. Here, pain-related gait parameters, whose criteria include (1) alteration in pain models, (2) correlation with nociceptive threshold, and (3) normalization by analgesics, were identified in representative models of neuropathic pain (spared nerve injury: coordination data) and inflammatory pain (intraplantar complete Freund's adjuvant: both coordination and intensity data) in the DigiGait™ and CatWalk™ systems. DigiGait™ had advantages in fixed speed (controlled by treadmill) and dynamic SFI, while CatWalk™ excelled in intrinsic velocity, intensity data, and high-quality 3D images. Insights into the applicability of each system may provide guidance for selecting the appropriate gait imaging system for different animal models and optimization for future pain research.