Alternative processing of the RNA transcribed from the calcitonin gene appears to result in the production of a messenger RNA in neural tissue distinct from that in thyroidal 'C' cells The thyroid mRNA encodes a precursor to the hormone calcitonin whereas that in neural tissues generates a novel neuropeptide, referred to as calcitonin gene-related peptide (CGRP) The distribution of CGRP-producing cells and pathways in the brain and other tissues suggests functions for the peptide in nociception, ingestive behaviour and modulation of the autonomic and endocrine systems The approach described here permits the application of recombinant DNA technology to analyses of complex neurobiological systems in the absence of prior structural or biological information

Production of a novel neuropeptide encoded by the calcitonin gene via tissue-specific RNA processing

The tachykinin peptide family

Immunohistochemical distribution of somatostatin-like immunoreactivity in the central nervous system of the adult rat

The tachykinin peptide family certainly represents one of the largest peptide families described in the animal organism. So far, more than 40 tachykinins have been isolated from invertebrate (insects, worms, and molluscs), protochordate, and vertebrate (skin, gastrointestinal tract, peripheral and central nervous system) tissues. Substance P (SP), first identified by bioassay as early as 1931 but sequenced only in 1971, several years after the elucidation of the structure of eledoisin from molluscan tissues and of physalaemin from amphibian skin, may be considered as a prototype of the tachykinins. Hitherto, as many as 19 tachykinins have been isolated from amphibian integument, and eight additional peptides have been isolated from amphibian gut and brain. Counterparts of skin tachykinins in mammalian tissues are SP, neurokinin A, and neurokinin B. Three main receptor subtypes for the tachykinins have been identified (NK1, NK2, and NK3), but their number is probably destined to increase. It is obvious that the peripheral and central effects of the tachykinins may substantially vary depending on the activation of different receptor subtypes. Matters are further complicated by the frequent capacity of the single tachykinins to bind, although with different affinity, to more receptors. It has been recognized that tachykinins have a variety of effects in physiological and pathological conditions, and there is evidence suggesting intrinsic neuroprotective and neurodegenerative properties of these neuropeptides. This review provides an update on the current body of knowledge regarding tachykinin occurrence and distribution in the animal kingdom, from the lowest invertebrates to man, and the physiological and pharmacological actions of tachykinins outlining the pregnant importance of this large peptide family.

The Tachykinin Peptide Family

Within the past decade, a large number of peptides have been described within the vertebrate central nervous system. Some of these peptides were previously known to be present in nonneural vertebrate tissues, as well as in lower species, in which they may serve as primitive elements of intercellular communication prior to the development of neuronal or endocrine systems. In vertebrates, these peptides are thought to have neurotransmitter or neuromodulatory roles and appear to be involved in the regulation of a number of homeostatic systems, although the mechanisms of their actions are still unclear.

https://science.sciencemag.org/content/sci/222/4627/975.full.pdf

Brain peptides: what, where, and why?

Polypeptide-hormone producing cells were localized in the alimentary tract and cerebral ganglion ofCiona intestinalis using cytochemical, immunocytochemical and electron-microscopical methods.

/pdf/gastro-intestinal-and-neurohormonal-peptides-in-the-385p6sbav3.pdf

Gastro-intestinal and neurohormonal peptides in the alimentary tract and cerebral complex of Ciona intestinalis (Ascidiaceae).

Indirect immunofluorescence studies using antisera to synthetic somatostatin, human calcitonin and substance P indicate, in the neural complex of the sea-squirt, Ciona intestinalis L, that these polypeptides are present in large perikarya situated at the periphery of the cerebral ganglion as well as in some smaller perikarya in the medulla In the medullary and transitional zone, there are nerve fibres that cross-react positively with anti-calcitonin and antisubstance P

/pdf/localization-of-somatostatin-substance-p-and-calcitonin-like-45d1rktvba.pdf

Localization of somatostatin-, substance P- and calcitonin-like immunoreactivity in the neural ganglion of Ciona intestinalis L. (Ascidiaceae).

Calcitonin-like immunoreactivity has been found with the peroxidase-anti-peroxidase (PAP) method in cells of the epithelium of the alimentary tract as well as in nerve cells and nerve fibers in the connective tissue underlying the epithelium of the alimentary tract of Ciona intestinalis L. The nature of these cells is discussed with reference to endocrine-like cells found in the alimentary tract of other protochordates and to the possible dual role of calcitonin occurring in the gastroenteropancreatic system, on the one hand, and in the nervous system, on the other.

Calcitonin-like immunochemical staining in the alimentary tract of Ciona intestinalis L.

Substance P-, neurotensin- and bombesin-like immunoreactivities were localised in some gill epithelial cells in the pharynx of Ciona intestinalis L No immunoreactivity was obtained with antisera to gastrin, glucagon, insulin, pancreatic polypeptide or calcitonin Some of the epithelial cells of the gills were shown to be argyrophilic with the Grimelius technique

/pdf/substance-p-neurotensin-and-bombesin-like-immunoreactivities-2cvp2uxrv1.pdf

S. Van Noorden

Papers

Gastro-intestinal and neurohormonal peptides in the alimentary tract and cerebral complex of Ciona intestinalis (Ascidiaceae).

Localization of somatostatin-, substance P- and calcitonin-like immunoreactivity in the neural ganglion of Ciona intestinalis L. (Ascidiaceae).

Calcitonin-like immunochemical staining in the alimentary tract of Ciona intestinalis L.

Substance P-, neurotensin- and bombesin-like immunoreactivities in the gill epithelium of Ciona intestinalis L.