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V Erspamer

Publications and source records attributed to V Erspamer.

At least 37 records · Page 2Linked to original sources
PubMed1986

Active peptides in the skins of two hundred and thirty American amphibian species.

Extracts prepared from dried or fresh skins of more than 200 American amphibian species were subjected to biological screening in order to determine occurrence and contents of peptides active on smooth muscle preparations, systemic blood pressure and, subordinately, external secretions, anterior pituitary and the central nervous system. The peptide families identified in skin extracts were as follows: caruleins (caerulein, phyllocaerulein), tachykinins (physalaemin, phyllomedusin), bombesins (phyllolitorin, [Leu8]phyllolitorin, rohdeilitorin), bradykinins (phyllokinin and others), sauvagine, dermorphins (dermorphin, [Hyp6]dermorphin), tryptophyllins (numerous peptides) and, finally, miscellaneous peptides. None of the above peptide families showed a widespread distribution, but all were restricted to particular amphibian genera or stocks. The hylid frogs of the Phyllomedusinae family occupy a unique position, as their skin displayed the greatest variety and abundance of active peptides ever found in any amphibian is destined to increase because numerous other peptide molecules await isolation, elucidation of structure and definition of possible biological activities.

Amphibian Proteins↗
PubMed1986

Indole-, imidazole- and phenyl-alkylamines in the skin of one hundred and forty American amphibian species other than bufonids.

Extracts prepared from dried or fresh skins of 140 American amphibian species, other than bufonids, were subjected to chemical and biological screening in order to determine the presence and concentrations of aromatic biogenic amines. The most frequent and abundantly occurring amine category was that of indolealkylamines, represented by their prototype 5-hydroxytryptamine and its N-methylated derivatives. Conjugated and cyclized indolealkylamines, typical for the toad skin, were apparently lacking. Phenylalkylamines were represented by two quaternary ammonium bases: leptodactyline and, very rarely, candicine. Leptodactyline was particularly abundant in leptodactylid frogs of the genus Leptodactylus. Histamine occurred in trace amounts in different species, in large amounts only in some Leptodactylus species of the "pachypus" section. On the other hand, N-methylated histamines and cyclized histamines (spinaceamines) were confined to the skin of Leptodactylus pentadactylus labyrinthicus. The possible taxonomical and evolutionary significance of amphibian skin amines is pointed out.

Amphibians↗
PubMed1985

Rohdei-litorin: a new peptide from the skin of Phyllomedusa rohdei.

The bombesin-litorin family of peptides is characterized by the common amino acid sequence-Gly-His-X-Met-NH2 at the C-terminus, where X is a hydrophobic or aromatic residue. A new member of this family, rohdei-litorin, has been isolated from amphibian skin and its structure shown to be: Glp-Leu-Trp-Ala-Thr-Gly-His-Phe-Met-NH2. This new peptide displayed a greater affinity than other members of the family for rat urinary bladder receptors. A litorin-like peptide, with high affinity for this kind of receptor, has already been described in mammalian spinal cord and named neuromedin B. Rohdei-litorin shares with neuromedin B the entire C-terminal octrapeptide and may be considered the amphibian counterpart of this mammalian neuropeptide.

Amino Acid Sequence↗
PubMed1985

A potent factor in extracts of the skin of the Australian frog, Pseudophryne coriacea. Apparent facilitation of transmitter release in isolated smooth muscle preparations.

Extracts of the skin of the Australian frog Pseudophryne coriacea (PsC) displayed potent stimulant effects on isolated smooth muscle preparations of intestine and similar effects on electrically-stimulated vas deferens preparations. These effects must be ascribed to an alkaloid, related in structure to the pumiliotoxins, a class of alkaloid compounds occurring in the skin of neotropical poison frogs. On the basis of results obtained with antagonists and blocking agents, it is suggested that the extract has a pre-synaptic, neurogenic point of attack and that it acts to facilitate the release of transmitters from nerve endings. Acetylcholine is the most important agent involved in the response to the extract by the intestinal muscle and noradrenaline in the response by vas deferens preparations. However, release of other aminergic or peptidergic transmitters may participate, positively or negatively, in the response.

Animals↗
PubMed1985

Phyllomedusa skin: a huge factory and store-house of a variety of active peptides.

The skin of the neotropical hylid frogs belonging to the subfamily. Phyllomedusinae is a formidable factory and store-house of a variety of active peptides belonging to seven distinct families: the caeruleins (represented by phyllocaerulein), the bradykinins (phyllokinin), the tachykinins (phyllomedusin), the bombesins (phyllolitorin, [Leu8]phyllolitorin, rohdei-litorin), sauvagine, the dermorphins (dermorphin, [Hyp6]dermorphin) and finally the tryptophyllins (a set of 8-11 members). Another linear peptide and three diketopiperazines should be added to the list. The biochemical and pharmacological positions of the Phyllomedusa peptides within their families is briefly discussed, dwelling upon some recent and controversial data.

Amino Acid Sequence↗
PubMed1985

Effects of sauvagine on behavioural arousal of mice.

The effects of natural and synthetic sauvagine on locomotor activity and ECS-induced seizures were studied in DBA/2 mice. A dose-dependent activity depression was evident following the administration of both compounds. Moreover they exerted a protective effect against ECS-induced seizures. This effect was naloxone-reversible, suggesting the involvement of endogenous opioids. In both series of experiments natural sauvagine was more effective than the synthetic compound.

Amphibian Proteins↗
PubMed1985

Bombesin effects on human GI functions.

In this article some of the actions of amphibian skin peptide Bombesin (BBS) on human gastrointestinal and pancreatic functions are reviewed. BBS causes increases of lower esophageal sphincter pressure, delay of gastric emptying, inhibition of mechanical activity of duodenum and jejunum and gallbladder emptying. BBS also releases in man gastrin and stimulates gastric acid secretion. BBS administration induces release of insulin, glucagon and pancreatic polypeptide from human Islet of Langerhans and causes secretion of pancreatic bicarbonates and enzymes in duodenal juice and release of pancreatic enzymes in blood stream.

Bombesin↗
PubMed1985

Peptides of the APUD system in amphibian skins.

Methanol extracted skins from 84 species of amphibia were screened, measuring by RIAs: gastrin-CCK, VIP, calcitonin, GIP, PP and motilin. G-CCK-like immunoreactivity was found in 97.6%; VIP-like immunoreactivity in 41%; CT-like immunoreactivity in 34%; GIP-like immunoreactivity in 10%; PP-like immunoreactivity in 40% and MT-like immunoreactivity in 60% of the samples. The use of a sequence-specific radioimmunoassay and of gel-chromatography confirmed the caerulein-CCK-8-like nature of the immunoreactive material. Detected amounts of the other peptides (VIP, CT, GIP, PP, MT) were too low for bioassay or chromatographic studies, thus leaving the question open if they are due to some kind of unspecific interferences or, most likely, to species-specificity differences of the used antisera.

APUD Cells↗
PubMed1984

Stimulation of crop sac and pituitary lactotrophs after intraventricular administration of dermorphin in pigeons.

The effects of dermorphin, a new potent opioid peptide, on structural and ultrastructural changes in the crop sac and in pituitary lactotrophs were assessed in pigeons (Columba livia). A single administration of dermorphin into the third cerebral ventricle (1 microgram) and the same dose repeated for 3 consecutive days both produced maximal crop sac stimulation, as documented by the presence of milk-like material as well as by scanning and transmission electron microscopy of crop sac mucosa. In addition, marked stimulatory effects were also observed in pituitary lactotrophs, as shown by stimulation of Golgi apparatus, enlargement of rough endoplasmic reticulum, increase in mitochondria size, and the presence of lysosomes and electron-opaque granules. The stimulatory effects of dermorphin on the crop sac and lactotrophs were completely prevented by naloxone, an antagonist at opiate receptors. Since dermorphin is a natural constituent of the avian brain, it has been suggested that this peptide may represent the still-obscure hypothalamic prolactin stimulatory factor.

Animals↗
PubMed1984

Active peptides in the skins of one hundred amphibian species from Australia and Papua New Guinea.

Extracts prepared from the dried skins of approximately one hundred amphibian species from Australia and Papua New Guinea were subjected to biological screening in order to determine the nature and amounts of peptides active on smooth muscle preparations and systemic blood pressure present in these extracts. The most frequently and abundantly occurring peptides were those of the caerulein, bombesin and tachykinin peptide families represented, respectively, by caerulein; litorin, Glu(OMe)2-litorin and Glu(OEt)2-litorin; uperolein and Lys5-Thr6-physalaemin. Bradykinin-like peptides seem to have a rather diffuse distribution, in the species examined, but so far no peptide of this family has been isolated and sequenced. The only angiotensin-like peptide ever found in amphibian skin, crinia angiotensin II, has been isolated from skin extracts of a few species, belonging to the genera Crinia, Geocrinia, Ranidella and Litoria. The array of peptides occurring in amphibians from Australia and Papua New Guinea is destined to increase, because several apparently novel peptides have been identified in skin extracts by bioassay and radioimmunoassay.

Amphibians↗
PubMed1982

Potent in vivo and in vitro prolactin inhibiting activity of sauvagine, a frog skin peptide.

The effect of sauvagine (SAU), a frog skin peptide, on prolactin (PRL) levels was studied in vivo and in vitro. Subcutaneous administration of SAU (20 micrograms/kg) reduced plasma PRL levels in normal adult male rats and suppressed the suckling-induced rise of PRL in lactating rats even at doses of 1 and 5 micrograms/kg. Perfusion of isolated and dispersed rat pituitary cells in vitro with increasing doses of SAU (from 5 x 10(-10) to 1.7 x 10(-8)M) induced a significant dose-related decrease of PRL secretion in the eluate. These results indicate that SAU is a potent PRL inhibiting factor and that its action is exerted at the pituitary level. If SAU or a SAU-related peptide is present in the mammalian brain, it can be tentatively hypothesized that this peptide plays an important role in the control of PRL secretion.

Amphibian Proteins↗
PubMed1981

The brain-gut-skin triangle: new peptides.

New data on tachykinins and bombesins are displayed and the present situation of research on the novel amphibian skin peptides sauvagine and dermorphin is illustrated. The potent stimulant effect of sauvagine on ACTH and beta-endorphin release has been confirmed both in vivo and on columns of isolated and dispersed rat pituitary cells, and similarly the potent inhibitory effect on PRL and GH release, both in the rat and man. Particular emphasis is laid on the occurrence of sauvagine-like immunoreactivity in fish urophysis and in amphibian nervous structures, including the retina. It is suggested that the long-searched corticotropin releasing factor and PRL release-inhibiting factor may be a sauvagine-like peptide. Dermorphin, in its turn, has been found to cause, by intracerebroventricular injection, not only analgesia and catalepsy, but also conspicuous EEG and behavioral changes in the rabbit and chick, as well as a sharp reduction in gastric emptying time and gastric acid output in the rat, together with marked stimulation of PRL release.

Adrenocorticotropic Hormone↗
PubMed1981

Radioimmunoassay of dermorphin-like peptides in mammalian and non-mammalian tissues.

A selective RIA for D-Ala2-Dermorphin (Der), a natural peptide extracted from amphibian skin, has been developed using an antibody raised in rabbits against Der which has been coupled to BSA through its phenolic hydroxyl groups of tyrosine residues with 2,4-Dichloro-6-methoxy-1,3,5-triazine. The cross-reactivity of this antibody with dermorphin analogs, C- and N-terminal fragments of dermorphin molecule, some opioid and gastrointestinal peptides was tested. Der-like immunoreactivity has been identified in tissue extracts of rats, frog and cephalopoda. Der-like peptides were purified by passing methanol extracts of the tissues through a Sephadex G25 column (16 x 100 cm) eluted with 0.1 M acetic acid at 4 degrees C. Der-like immunoreactivity from neural tissue of Dosidicus gigas, Eledone moscata, and rat brain showed a good agreement with an authentic sample of synthetic dermorphin.

Animals↗
PubMed1981

Synthetic peptides related to the dermorphins. I. Synthesis and biological activities of the shorter homologues and of analogues of the heptapeptides.

Dermorphins are potent opiate-like peptides isolated from the skin of some species of frogs. They are characterized by the presence of a D-amino acid residue, which is crucial for bioactivity. A number of analogues were prepared in order to evaluate the structure-activity relationships. The syntheses were accomplished either by conventional or solid-phase procedures. In vitro assays included both guinea pig ileum (GPI) and mouse vas deferens (MVD) preparations. Central analgesic (tail-flick and hot plate tests) and cataleptic activities were determined in the rat by intracerebroventricular route. The potency of dermorphin (H- Tyr-D-Ala-Phe-Gly-Tyr-Pro-Ser-NH2) in the different tests was: GPI: IC50 = 3.3 nM; MVD: IC50 = 29 nM; hot plate: ED50 = 13.3 pmol/rat; tail-flick: ED50 = 23 pmol/rat; catalepsy: ED50 = 130 pmol/rat.

Analgesics↗
PubMed1981

Amino acid composition and sequence of dermorphin, a novel opiate-like peptide from the skin of Phyllomedusa sauvagei.

Dermorphin, a heptapeptide with very potent opiate-like activity, has been isolated from methanol extracts of the skin of the South American frog Phyllomedusa sauvagei. The amino acid sequence of the peptide is: H-Try-D-Ala-Phe-Gly-Tyr-Pro-Ser-NH2. Dermorphin presents striking differences from the known enkephalins; it offers a surprising example of a peptide from Vertebrata containing a D-amino acid residue in its sequence.

Amino Acid Sequence↗