The tachykinin peptide family

Isolation of a sialogogic peptide from bovine hypothalamic tissue and its characterization as substance P

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

Tachykinin receptor types: Classification and membrane signalling mechanisms

Several vasoactive peptides administered intracisternally have been assessed for the effect of lowering the core temperature of rats exposed to cold. Peptides structurally related to neurotensin lower core temperature while those related to substance P do not. The tetradecapeptide bombesin, orginally isolated from the extracts of the skin of the frog Bombina bombina, is 10(4) times more potent than neurotensin in lowering core temperature, with a minimal effective dose less than or equal to 1 nanogram per 200 grams of body weight. Thus bombesin is one of the most potent peptides reported to affect the central nervous system.

https://science.sciencemag.org/content/sci/196/4293/998.full.pdf

Bombesin:potent effects on thermoregulation in the rat.

Viene descritto il procedimento che ha permesso l'isolamento e il chiarimento della struttura chimica dellafisalemina, il principale dei polipeptidi attivi della pelle diPhysalaemus fuscumaculatus, anfibio dell'Argentina. La fisalemina, strettamente vicina all'eledoisina anche da un punto di vista chimico e, come questa, dotata di potente azione sulla muscolatura liscia vasale ed extravasale. Essa e nettamente distinguibile, mediante saggi paralleli, da tutti gli altri polipeptidi biogeni finora noti.

Structure and pharmacological actions of physalaemin, the main active polypeptide of the skin of Physalaemus fuscumaculatus.

Gli estratti di pelle fresca o secca diPhysalaemus fuscumaculatus contengono una sostanza attiva di natura polipeptidica, laphysalaemina, dotata di potente azione ipotensiva e di intensa azione stimolante su alcuni muscoli lisci extravasali. La physalaemina e facilmente distinguibile, mediante saggi paralleli, da tutti gli altri polipeptidi biogeni finora noti, compresa la eledoisina che alla physalaemina s'accosta per parecchie delle sue azioni farmacologiche.

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Occurrence of an eledoisin-like polypeptide (physalaemin) in skin extracts ofPhysalaemus fuscumaculatus

Gli estrati di pelle di alcuni comuni anfibi nostrani (Rana esculenta, Rana temporaria) e, ancor piu, di certi anfibi sudamericani del generePhyllomedusa contengono rilevanti quantitativi di polipeptidi bradichinino-simili. Negli estratti diPhyllomedusa sauvagi ne sono stati identificati almeno tre, a mezzo di una semplice cromatografia su colonna di allumina basica: polipeptide A, assai simile alla bradichinina per le sue proprieta farmacologiche; polipeptide B, dotato di prolungata ed intensa azione ipotensiva; polipeptide C, particolarmente attivo sull'ileo di cavia. Sono in corso ricerche dirette all'isolamento di questi polipeptidi e al chiarimento della loro struttura chimica.

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G. Bertaccini

Papers

Structure and pharmacological actions of physalaemin, the main active polypeptide of the skin of Physalaemus fuscumaculatus.

Occurrence of an eledoisin-like polypeptide (physalaemin) in skin extracts ofPhysalaemus fuscumaculatus

Occurrence of bradykinin-like substances in the amphibian skin