Developmental pattern of axonal pathways in the house shrew maxillary nerve

Anatomical study of the pancreas in the house musk shrew (Suncus murinus), with special reference to the blood supply and innervation

To examine the macroscopic structure, blood supply, and innervation of the pancreas in the house musk shrew (Suncus murinus), we performed gross anatomical dissection and whole-mount immunostaining of the autonomic nerve of Suncus pancreases based on neurofilament protein (NFP) immunoreactivity. The adult Suncus pancreas is clearly separated into right and left lobes that are not fused. The right lobe of the Suncus pancreas is located in the dorsum of the duodenum and to the right of the common bile duct independently. The right lobe is supplied by branches of the superior mesenteric artery, and is innervated by branches that originate from the superior mesenteric plexus and run along the arterial branches of the superior mesenteric artery. The left lobe occupies 9/10 of the entire pancreas and is located to the left of the common bile duct. It is supplied mainly by branches of the splenic and common hepatic arteries, and is innervated by branches that originate from the celiac plexus and run along the splenic and common hepatic arteries. According to previous studies on the blood supply and innervation of the human pancreas, the right and left lobes of the Suncus pancreas correspond to the pancreatic parts derived from the ventral and dorsal pancreatic buds. The current results suggest that the Suncus pancreas is a suitable experimental model for studying the development of the human pancreas.

Postnatal development of EEG patterns, catecholamine contents and myelination, and effect of hyperthyroidism in Suncus brain

The postnatal development of the central nervous system (CNS) in house musk shrew in the early stage of maturation was studied. The electroencephalogram (EEG) and visual evoked potential (VEP) in association with catecholamine contents and myelin basic protein (MBP) immunoreactivity were carried out from the 1st to the 20th day of postnatal age. Different EEG patterns which were specific to behavioral states (awake and drowsy) were first recorded on the 5th day, and the total power which was obtained by power spectrum analysis increased after this stage. The latencies of all peaks in VEP markedly shortened between the 5th and the 7th day. Noradrenalin (NA) content of the brain showed a slight increase after the 3rd day, and reached maximum levels on the 7th day, which was delayed a few days compared to dopamine (DA). In hyperthyroidism, the peak latency of VEP was shortened and biosynthesis of NA in cerebral cortex and DA in hippocampus was accelerated. The most obvious change in MBP-immunoreactivity of the telencephalon occurred from the 7th to the 10th day. These morphological changes in the brain advanced at the identical time-course to those in the electrophysiological development and increment of DA and NA contents.