Endothelin-1 as a neuropeptide: neurotransmitter or neurovascular effects?

Endothelin-1 (ET-1) is an endothelium-derived peptide that also possesses potent mitogenic activity. There is also a suggestion the ET-1 is a neuropeptide, based mainly on its histological identification in both the central and peripheral nervous system in a number of species, including man. A neuropeptide role for ET-1 is supported by studies showing a variety of effects caused following its administration into different regions of the brain and by application to peripheral nerves. In addition there are studies proposing that ET-1 is implicated in a number of neural circuits where its transmitter affects range from a role in pain and temperature control to its action on the hypothalamo-neurosecretory system. While the effect of ET-1 on nerve tissue is beyond doubt, its action on nerve blood flow is often ignored. Here, we review data generated in a number of species and using a variety of experimental models. Studies range from those showing the distribution of ET-1 and its receptors in nerve tissue to those describing numerous neurally-mediated effects of ET-1

Duplication of the parotid duct: a previously unreported anomaly

A hitherto unreported duplication of the parotid duct in a 63-year-old man is reported. The ducts were found in the right cheek during cadaver dissection. The surrounding connective tissue of the ducts was removed and a photograph was taken. These two parotid ducts were then removed and fixed in a 10% formalin solution, embedded in paraffin blocks and the sections stained with hematoxylin eosin. The histologic findings showed that both had the normal ductal columnar epithelium. There was only one parotid duct in the left cheek