Axons and axon terminals are widely believed to lack the capacity to synthesize proteins, relying instead on the delivery of proteins made in the perikaryon. In agreement with this view, axoplasmic proteins synthesized by the isolated giant axon of the squid are believed to derive entirely from periaxonal glial cells. However, squid axoplasm is known to contain the requisite components of an extra-mitochondrial protein synthetic system, including protein factors, tRNAs, rRNAs, and a heterogeneous family of mRNAs. Hence, the giant axon could, in principle, maintain an endogenous protein synthetic capacity. Here, we report that the squid giant axon also contains active polysomes and mRNA, which hybridizes to a riboprobe encoding murine neurofilament protein. Taken together, these findings provide direct evidence that proteins (including the putative neuron-specific neurofilament protein) are also synthesized de novo in the axonal compartment.
ensp;The distribution and colocalisation of nicotinamide adenine dinucleotide phosphate reduced-diaphorase (NADPH-d)-/nitric oxide synthase (NOS)-containing (nitrergic) neurons in the innervation of the duck ureter have been studied using histochemistry and immunohistochemistry. Quantitative analysis showed that nitrergic neurons made up 60% and 70% of the total intramural and adventitial neuronal populations, respectively. About 40% of intramural nitrergic neurons expressed VIP-immunoreactivity, and about 75% of nitrergic adventitial neurons expressed TH-immunoreactivity. The density of nitrergic adventitial neurons was significantly greater in the lower tract than in the upper and intermediate tracts. Nerve lesioning experiments showed that the majority of ureteral nitrergic innervation was extrinsic in origin; nitrergic adventitial neurons primarily projected caudocranially, whereas NOS-immunoreactive and NOS-/VIP-immunoreactive intramural neurons primarily projected craniocaudally. These findings suggest that, in birds, the nitrergic innervation plays a role in ureteral functions such as epithelial mucosecretion, muscular motility, and the closing and/or opening of the ureteral papilla.
The hypophysis of Bubalus buffalus was examined morphologically and compared to that of the bovine. The morphology and behavior of the vessels supplying the hypophysis and their contribution to the hypophyseal portal system were described. We found characteristic vascular arches between the pars tuberalis and the infundibulum from which the portal vessels originate. These vessels may be divided into long and short vessels, have different origins and extension, and branch in different regions of the anterior lobe.
The intrinsic laryngeal musculature of rabbit was studied using various neurohistological techniques. The vegetative and sensory nerve terminals are present in abundance, while the proprioceptors are seemingly absent. Furthermore, simple motor endplates, sometimes furnished with ultraexpansional fibers, complex end-plates, or ‘en grappe’ are described. Their abundance within a musculature lacking in muscle-spindles is indicative of a possible vicarious function.
The palatine tonsil was studied comparatively on 10 heads each of ox and buffalo. On latex casts the branches of the tonsillar sinus were demonstrated. Histological study included the epithelium of the tonsillar sinus, the connective tissue of capsule and septa, the lymphatic tissue and intra and extracapsular glandular lobules
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