Enkephalin-, VIP- and substance P-like immunoreactivity in the carotid body

Abstract

The carotid body type I cell contains amines and has features, both morphological and cytochemical, which indicate that it may also produce a peptide. Many regulatory peptides are now known to be present in both central and peripheral tissues. In the periphery these neuropeptides occur in both classical endocrine (APUD) cells and the neurones of the autonomic nervous system. We have now investigated the possible presence of neuropeptides in the cat carotid body using both immunocytochemistry and radioimmunoassay. Met- and Leu-enkephalin-like material occurred in considerable quantities in carotid body extracts and enkephalin-like immunoreactivity was localised in type I cells. Both vasoactive intestinal polypeptide (VIP)- and substance P-like immunoreactivity was also present but was localised in nerve fibres distributed throughout the organ. These active neuropeptides are widely distributed in mammalian tissues, forming a diffuse regulatory system which now seems to include the carotid body.

Distribution of Substance P-Containing and Catecholaminergic Nerve Fibers in the Rabbit Carotid Body: An Immunohistochemical Study in Combination with Catecholamine Fluorescent Histochemistry.

“…As shown in Table 1 examined, except for humans, and the rabbit in this study. In the cat and rat, it is thought taht SP fibers are involved in chemoreception (LUNDBERG et al, 1979a;HELKE et al, 1980;JACOBOWITZ and HELKE, 1980;WHARTON et al, 1980). Figure 2C, in which most SP fibers are located near the clusters of glomus cells that have been considered to be chemoreceptor cells, with some of them encircling the clusters, strongly supports this suggestion in cat and rat.…”

“…In the last decade, substance P (SP), which was originally studied in sensory systems, has been immunohistochemically demonstrated in the nerve fibers and the glomus cells in the carotid body of humans (SMITH et al, 1990) and seven experimental species: the cat (LUNDBERG et al, 1979a;CUELLO and MCQUEEN, 1980;WHARTON et al, 1980;WANG et al, 1982;PATES and CHEN, 1987;SCHEIBNER et al, 1988;PRABHAKAR et al, 1989), guinea pig (KUMMER et al, 1989a), rat (HELKE et al, 1980;JACOBOWITZ and HELKE, 1980;YATES and CHEN, 1987), chicken (KAMEDA, 1989), frog, salamander, and newt (KUSAKABE et al, 1991(KUSAKABE et al, , 1993(KUSAKABE et al, , 1994KUSAKABE, 1992). There is, however, no immunohistochemical evidence regarding the rabbit carotid body.…”

Innervation of synovial membrane and meniscus

“…All the antibodies were kindly donated by Dr. Julia Polak of Hammersmith Hospital, London; their specificities have previously been confirmed (Wharton et al 1979(Wharton et al , 1980. To diminish the background fluorescence the sections were incubated in normal sheep serum, diluted 1:30.…”

Characterization of opioid receptors in the cat carotid body involved in chemosensory depression in vivo

“…[Met]enkephalin was used as the 'standard' against which responses to analogues were compared because the cat carotid body contains three times more [Met] than [Leu]enkephalin-like material (Wharton et al, 1980). The rank order of potency as chemodepressants showed that analogues with high affinity for 6-opioid receptors were more active than those which were i I I predominantly p-or K-receptor agonists; the #L-receptor agonist morphiceptin (Chang et al, 1981) was inactive in the doses used.…”