V Stauber | PubMed Health

PubMed1988

The co-localisation of substance P and VIP in cholinergic-type terminals of the rat parotid gland.

Parotid glands from the rat were examined for substance P (SP) and vasoactive intestinal polypeptide (VIP)-like immunoreactivity with the peroxidase-antiperoxidase (PAP) and immunogold methods. The majority of nerve terminals associated with the acinar secretory cells contained numerous small agranular vesicles measuring 40-60 nm in diameter and a few larger vesicles which had an electron-dense core and measured 90-120 nm in diameter. Electron-dense peroxidase reaction product indicative of SP and/or VIP-like immunoreactivity was found within the larger dense-cored vesicles and attached to the outer membrane of the small agranular vesicles. Some nerve terminals associated with the acinar cells contained no reaction product irrespective of whether sections were incubated for SP or VIP. With the immunogold method gold particles indicative of SP and/or VIP-like immunoreactivity were found associated with the larger dense-cored vesicles with very little gold labelling over the small agranular vesicles. When ultrathin sections were incubated for both SP and VIP-like immunoreactivity all of the labelled terminals examined contained gold particles indicative of the presence of both peptides. In several terminals individual dense-cored vesicles contained gold particles of different sizes which indicates co-existence of SP and VIP within the same vesicle. Several nerve terminals associated with the acinar cells contained no gold labelling of their synaptic vesicles. Occasionally nerve terminals were found around blood vessels that were positive for SP-like immunoreactivity and VIP-like immunoreactivity but none was found, using the immunogold method, that contained both peptides. Very few nerve terminals were found associated with ducts and none contained reaction product or gold particles indicative of SP or VIP-like immunoreactivity. The ultrastructural features of the nerve terminals containing SP and/or VIP-like immunoreactivity could not be distinguished from those that have been described as representing cholinergic terminals. The fact that the postganglionic parasympathetic secretomotor neurons contain, in addition to acetylcholine, two neuropeptides and the possible functional implications thereof are discussed.

Animals↗

PubMed1985

Axonal regeneration through a peripheral nerve implanted into a brain cavity.

A cavity was prepared in the rat parietal cortex by suction, filled with gel foam and left for 3 weeks during which time it became highly vascularised. Into this 3-week-old capillary bed a 5 mm length of autologous common peroneal nerve was implanted. Animals were killed at various time intervals up to 7 months after implantation of the nerve segment. The ultrastructural features of the vascular bed before and after implantation of the nerve segment were compared. In the absence of a peripheral nerve implant no axons were found within the cavity. However, at 5 weeks after implantation numerous axon-like profiles and capillaries containing fenestrations were observed within the implant. Eight weeks after implantation of the peripheral nerve both myelinated and non-myelinated axons were observed within the implant and in the surrounding capillary bed. No obvious increase in the number of axons was observed with increasing time periods. To investigate the origin of the axons within the vascular bed and/or implant the fluorochrome true blue was injected into the cavity 7 months after implantation of the nerve. Three days later selected areas of the brain, the trigeminal, superior cervical and otic ganglia were examined for retrogradely labelled fluorescent cells. Labelled cells were found adjacent to the cavity and in the ipsilateral trigeminal and superior cervical ganglia. The significance of these results in relation to the enhancement of axonal regeneration from the damaged central nervous system (CNS) is discussed.

Animals↗