A direct action of human calcitonin gene-related peptide on isolated osteoclasts

ABSTRACT The calcitonin gene encodes a small family of peptides: calcitonin, calcitonin gene-related peptide (CGRP) and katacalcin. Whereas calcitonin is concerned with skeletal maintenance, the function, if any, of katacalcin is still unknown. In the present study we have assessed resorption of human cortical bone substrate by isolated rat osteoclasts and have shown that CGRP acts directly on the osteoclast to inhibit bone resorption. The three CGRP peptides (rat, human(a) and human(β)) caused an almost equivalent decrease in osteoclastic bone resorption and were approximately 1000-fold less potent than human calcitonin in this respect. The responses of human calcitonin and human CGRP(α) were additive. Furthermore, prior treatment with trypsin to destroy receptors abolished the responsiveness of osteoclasts to CGRP and calcitonin. The carboxyl- and amino-terminal fragments of CGRP were found not to inhibit bone resorption, suggesting that the whole molecule of CGRP is necessary for biological activity. We have therefore suggested that the calcitonin-like effects of CGRP, seen both in vivo in the rat bioassay and in vitro in organ cultures, are due to the direct action of CGRP on the osteoclast, probably mediated through the calcitonin receptor. Though it is unlikely that CGRP is involved in the regulation of plasma calcium, the peptide may be an important local regulator of bone cell function. J. Endocr. (1987) 115,511–518

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Calcitonin gene related peptide relaxes cholecystokinin-induced contraction in guinea pig gallbladder strips in vitro

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y92-225 ◽

1992 ◽

Vol 70 (12) ◽

pp. 1571-1575 ◽

Cited By ~ 7

Author(s):

L. W. Kline ◽

P. K. T. Pang

Keyword(s):

Smooth Muscle ◽

Guinea Pig ◽

Calcitonin Gene Related Peptide ◽

Intestinal Smooth Muscle ◽

Human Calcitonin ◽

Peptide Receptor ◽

Related Peptide ◽

Calcitonin Gene ◽

Dose Dependent

Calcitonin gene related peptide has been shown to relax vascular and intestinal smooth muscle. This study examines the effects of calcitonin gene related peptide on cholecystokinin-induced contraction of guinea pig gallbladder strips in vitro. Calcitonin gene related peptide was found to cause a dose-dependent relaxation of cholecystokinin-induced tension, which was blocked by the calcitonin gene related peptide receptor antagonist human calcitonin gene related peptide8–37. Previous studies demonstrated that calcitonin gene related peptide acted directly on guinea pig gallbladder smooth muscle to inhibit acetylcholine- or KCl-induced contraction. The present results further confirm that calcitonin gene related peptide acts directly on the smooth muscle. In addition, the use of L-NG-nitroarginine methyl ester, glibenclamide, and other agents strongly suggests that calcitonin gene related peptide also acts by way of the nonadrenergic noncholinergic nervous system, to induce the relaxation of cholecystokinin-induced contraction observed in the guinea pig gallbladder strips.Key words: calcitonin gene related peptide, gallbladder, cholecystokinin.

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Structure-activity relationship of human calcitonin-gene-related peptide

Biochemical Journal ◽

10.1042/bj2690775 ◽

1990 ◽

Vol 269 (3) ◽

pp. 775-780 ◽

Cited By ~ 33

Author(s):

M Zaidi ◽

S D Brain ◽

J R Tippins ◽

V Di Marzo ◽

B S Moonga ◽

...

Keyword(s):

Blood Flow ◽

Biological Activity ◽

Bone Resorption ◽

Structural Similarity ◽

Calcitonin Gene Related Peptide ◽

Human Calcitonin ◽

Oedema Formation ◽

Rabbit Skin ◽

Related Peptide ◽

Calcitonin Gene

The calcitonin-calcitonin-gene-related peptide (CGRP) gene complex encodes a small family of peptides: calcitonin, CGRP and katacalcin. Calcitonin is a circulating hormone that prevents skeletal breakdown by inhibiting the resorption of bone by osteoclasts. CGRP, a potent vasodilator, is involved in normal regulation of blood flow. The calcitonins structurally resemble the CGRP peptides, and both are known to cross-react at each others' receptors. The present study was undertaken to examine the structural prerequisites for biological activity of the intact CGRP molecule. We therefore prepared eight chymotryptic and tryptic fragments of CGRP and synthesized its acetylated and S-carboxyamidomethylcysteinyl analogues. The analogues were purified by h.p.l.c. and their structures were confirmed by fast-atom bombardment mass spectrometry. We have examined the effects of structurally modified analogues and fragments of human CGRP in a calcitonin-receptor-mediated assay, the osteoclast bone resorption assay, and in one or two CGRP-receptor-mediated assays, the rabbit skin blood flow assay and the oedema formation assay. The results showed that (1) in the osteoclast bone resorption assay, both CGRP peptides, alpha and beta, were equipotent, and were both at least 1000-fold were both approx. 1000-fold more potent than salmon calcitonin; human calcitonin had no effect; (3) the bis- and N-acetylated CGRP analogues retained reduced levels of biological activity in all assays, whereas S-carboxyamidomethylcysteinyl-human CGRP was without activity; and (4) all tryptic and chymotryptic fragments of CGRP were without biological activity, with the exception of hCGRP-(Ala1-Lys35): this fragment had much reduced activity compared with the intact peptide in inhibiting osteoclastic bone resorption and increasing blood flow in the rabbit skin. The results suggest that: (1) calcitonin and CGRP act at distinct receptors to mediate different physiological effects; (2) minor amino acid substitutions, as between the alpha and beta forms of CGRP (these two forms have 94% structural similarity) do not result in differences in biological activity; (3) the intact peptide is required for full biological activity of the CGRP molecule, and even the loss of two amino acids at the C-terminus of the molecule results in a marked decrease in activity; (4) the disulphide bridge appears to play an important role in the interaction of the intact CGRP molecule with its receptor; and (5) the C-terminal region is probably necessary for the peptide to assume the right conformation in the interaction with the receptor.

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Calcitonin gene-related peptide receptor antagonist human CGRP-(8-37)

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1989.256.2.e331 ◽

1989 ◽

Vol 256 (2) ◽

pp. E331-E335 ◽

Cited By ~ 21

Author(s):

T. Chiba ◽

A. Yamaguchi ◽

T. Yamatani ◽

A. Nakamura ◽

T. Morishita ◽

...

Keyword(s):

Plasma Membrane ◽

Adenylate Cyclase ◽

Calcitonin Gene Related Peptide ◽

Human Calcitonin ◽

Liver Plasma Membrane ◽

Related Peptide ◽

Calcitonin Gene ◽

Liver Membranes ◽

Calcitonin Receptors ◽

Stimulation Of

From this study, we predicted that the human calcitonin gene-related peptide (hCGRP) fragment hCGRP-(8-37) would be a selective antagonist for CGRP receptors but an agonist for calcitonin (CT) receptors. In rat liver plasma membrane, where CGRP receptors predominate and CT appears to act through these receptors, hCGRP-(8-37) dose dependently displaced 125I-[Tyr0]rat CGRP binding. However, hCGRP-(8-37) had no effect on adenylate cyclase activity in liver plasma membrane. Furthermore, hCGRP-(8-37) inhibited adenylate cyclase activation induced not only by hCGRP but also by hCT. On the other hand, in LLC-PK1 cells, where calcitonin receptors are abundant and CGRP appears to act via these receptors, the bindings of 125I-[Tyr0]rat CGRP and 125I-hCT were both inhibited by hCGRP-(8-37). In contrast to liver membranes, interaction of hCGRP-(8-37) with these receptors led to stimulation of adenosine 3',5'-cyclic monophosphate (cAMP) production in LLC-PK1 cells, and moreover, this fragment did not inhibit the increased production of cAMP induced not only by hCT but also by hCGRP. Thus hCGRP-(8-37) appears to be a useful tool for determining whether the action of CGRP as well as that of CT is mediated via specific CGRP receptors or CT receptors.

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Tapentadol inhibits calcitonin gene-related peptide release from rat brainstem in vitro

Peptides ◽

10.1016/j.peptides.2014.03.009 ◽

2014 ◽

Vol 56 ◽

pp. 8-13 ◽

Cited By ~ 6

Author(s):

Maria Cristina Greco ◽

Lucia Lisi ◽

Diego Currò ◽

Pierluigi Navarra ◽

Giuseppe Tringali

Keyword(s):

Calcitonin Gene Related Peptide ◽

Related Peptide ◽

Calcitonin Gene ◽

Peptide Release ◽

Rat Brainstem

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Calcitonin gene-related peptide is a survival factor, inhibiting apoptosis in neonatal rat gubernaculum in vitro

Journal of Pediatric Surgery ◽

10.1016/j.jpedsurg.2008.11.039 ◽

2009 ◽

Vol 44 (8) ◽

pp. 1497-1501 ◽

Cited By ~ 13

Author(s):

Jessica J. Chan ◽

Pam J. Farmer ◽

Bridget R. Southwell ◽

Magdy Sourial ◽

John M. Hutson

Keyword(s):

Calcitonin Gene Related Peptide ◽

Neonatal Rat ◽

Related Peptide ◽

Survival Factor ◽

Calcitonin Gene

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Age-Related Decreases of Calcitonin Gene-Related Peptide (CGRP)-Induced Hypotension in vivo and Vasorelaxant Responses in vitro in Rats

Peptides: The Wave of the Future ◽

10.1007/978-94-010-0464-0_348 ◽

2001 ◽

pp. 746-747

Author(s):

Gabriel H. H. Chan ◽

Ronald R. Fiscus

Keyword(s):

Calcitonin Gene Related Peptide ◽

Induced Hypotension ◽

Related Peptide ◽

Age Related ◽

Calcitonin Gene

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Renal microvascular actions of calcitonin gene-related peptide

AJP Renal Physiology ◽

10.1152/ajprenal.1998.274.6.f1078 ◽

1998 ◽

Vol 274 (6) ◽

pp. F1078-F1085 ◽

Cited By ~ 12

Author(s):

Martina Reslerova ◽

Rodger Loutzenhiser

Keyword(s):

Angiotensin Ii ◽

Rat Kidney ◽

Elevated Pressure ◽

Calcitonin Gene Related Peptide ◽

Dependent Manner ◽

Concentration Dependent Manner ◽

Renal Vasoconstriction ◽

Related Peptide ◽

Calcitonin Gene

Calcitonin gene-related peptide (CGRP) is a potent vasodilator that is suggested to act via ATP-sensitive K channels (KATP). In the present study, we examined the actions of CGRP on pressure- and angiotensin II-induced vasoconstriction, using the in vitro perfused hydronephrotic rat kidney. Elevated pressure (from 80 to 180 mmHg) and 0.1 nM angiotensin II elicited similar decreases in afferent diameter in this model. CGRP inhibited myogenic reactivity in a concentration-dependent manner, completely preventing pressure-induced constriction at 10 nM (95 ± 10% inhibition). These effects were partially attenuated by 10 μM glibenclamide (62 ± 16% inhibition, P = 0.025), indicating both KATP-dependent and -independent actions of CGRP. In contrast, 10 nM CGRP inhibited angiotensin II-induced vasoconstriction by only 54 ± 11%, and this action was not affected by glibenclamide (41 ± 11%, P = 0.31). CGRP also inhibited the efferent arteriolar response to angiotensin II in the absence and presence of glibenclamide. Pinacidil (1.0 μM), a KATP opener also preferentially inhibited pressure- vs. angiotensin II-induced vasoconstriction (97 ± 5 and 59 ± 13% inhibition, respectively; P = 0.034). We conclude that the renal vasodilatory mechanisms of CGRP are pleiotropic and involve both KATP-dependent and -independent pathways. The effectiveness of CGRP in opposing renal vasoconstriction and the role of KATP in this action appear to depend on the nature the underlying vasoconstriction. We suggest that this phenomenon reflects an inhibition of KATP activation by angiotensin II.

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