Exploring the nervous system and some effector organs in veterinary species with a focus on calcium-binding proteins, serotonergic, endocannabinoid and peptidergic systems

This study aims to enhance scientific knowledge in veterinary anatomy by analyzing different regions of the central nervous system (CNS), peripheral nervous system (PNS), and effector organs in various species, focusing on key biological systems. For the CNS, research was conducted on: 1) the entorhinal cortex (EC) of the bottlenose dolphin, using immunoperoxidase to examine the distribution, cytoarchitecture, and morphology of three calcium-binding proteins (calretinin, calbindin D-28K, and parvalbumin); 2) the amygdaloid complex (AC) of the rat and sheep. In rats, we studied the vasoactive intestinal peptide (a peptidergic system component) and its co-localization with the GABAergic system using immunoperoxidase and immunofluorescence. In sheep, we investigated AC connectivity with the brain using diffusion tensor imaging. 3) The optic lobe (OL) of the honeybee, where immunofluorescence against the serotonin transporter (SERT) was used to assess serotonergic system distribution and its correlation with aggressive behavior. For the PNS, we examined: 1) the trigeminal ganglion (TG) of the horse, studying cannabinoid receptor distribution in different cell types using immunofluorescence and immunoperoxidase; 2) the enteric nervous system (ENS) of the dolphin, focusing on substance P (SP) and neuronal nitric oxide synthase (nNOS) to distinguish excitatory and inhibitory neurons. Effector organs studied included: 1) the skin of dogs with atopic dermatitis (AD); 2) the synovial membrane of the metacarpophalangeal joint in horses and 3) the hip and stifle joints in dogs. In these tissues, cannabinoid receptor distribution was analyzed due to their role in pain and inflammation. This work provides an overview of existing literature and presents scientific articles that address gaps in knowledge, establishing fundamental anatomical insights for future research.