Journal ArticleDOI
Bufokinin: actions and distribution in the toad cardiovascular system.
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The effects of bufokinin on systemic blood pressure and heart rate in the anaesthetized toad and the distribution ofbufokinin‐like immunoreactivity in the toad vasculature are investigated.Abstract:
1. Bufokinin is a substance P-like neuropeptide and potent spasmogen isolated from the intestine of the cane toad Bufo marinus. In the present study, we investigated the effects of bufokinin on systemic blood pressure and heart rate in the anaesthetized toad and the distribution of bufokinin-like immunoreactivity in the toad vasculature. 2. Intravenous bufokinin caused a dose-dependent fall in systemic blood pressure (maximum fall 20 mmHg) with an ED50 of 2.9 pmol. At higher doses, the effect was prolonged and blood pressure did not return to baseline within 60 min. There was no significant change in heart rate associated with hypotension. 3. Bufokinin-like immunoreactivity was mapped in whole mounts of toad blood vessels and organs using a mouse polyclonal antibody BK3 (at 1:5000) and the avidin-biotin method. Bufokinin-immunoreactive fibres were associated with most blood vessels examined: a moderately dense perivascular network of varicose fibres was present around renal arteries, with sparser immunoreactive fibres in the ventral aorta, sciatic artery, anterior abdominal vein and hepatic portal vein. 4. Bufokinin-immunoreactive fibres, mainly following blood vessels, were seen in whole mounts of the urinary/bladder and tongue, but not in the air sac. In the heart ventricle, varicose fibres were found in the valve cusps, intracardiac ganglia, epicardium and myocardium close to the endocardium, but not in the rest of the myocardium. 5. The vasodepressor action of bufokinin and the presence of bufokinin-like immunoreactivity in varicose fibres in various vessels suggest a role for bufokinin in haemodynamic regulation and/or sensory nerve function in the toad. The lack of any reflex tachycardia in response to the falls in blood pressure was of note.read more
Citations
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Journal ArticleDOI
Tachykinin peptides and receptors: putting amphibians into perspective.
Lu Liu,Elizabeth Burcher +1 more
TL;DR: It is concluded that tachykinin peptides and receptors are well conserved in terms of their structures, physiological functions and coupling mechanisms during tetrapod evolution.
Book ChapterDOI
The Tachykinin Peptide Family, with Particular Emphasis on Mammalian Tachykinins and Tachykinin Receptor Agonists
TL;DR: The NH2 terminal extension to the NKA sequence in these tachykinins has only minor effects on potency in vitro but the greater stability of these agonists in vivo results in a different spectrum of activities.
Journal ArticleDOI
Bufokinin: immunoreactivity, receptor localization and actions in toad intestine and mesenteric circulation.
TL;DR: A role for bufokinin as an endogenous spasmogen and hemodynamic regulator in the toad intestine is supported by mapped immunoreactivity and binding sites.
Journal ArticleDOI
Quantitative structure–activity analyses of bufokinin and other tachykinins at bufokinin (bNK1) receptors of the small intestine of the cane toad, Bufo marinus
TL;DR: ThePotencies of most full-length peptides were well predicted using the leave-one-out procedure, as were the potencies of a series of model Ala-substituted BUFs, thus emphasising the potential utility of these equations in the design of new ligands interacting with tachykinin receptors.
Characterization of Substance P (SP) Aminoterminal SP (1-7) Binding in Brain Regions and Spinal Cord of the Male Rat : Studies on the Interaction with Opioid Related Pathways
TL;DR: Binding sites for substance P(1-7), SP( 1-7) have been identified and characterized for the first time in crude membrane fraction from rat CNS using tritiated ([3H]) SP(1 -7) as tracer.
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Substance P-like immunoreactivity in nerves associated with the vascular system of guinea-pigs
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Journal ArticleDOI
The brain-gut-skin triangle: new peptides.
Vittorio Erspamer,Pietro Melchiorri,Maria Broccardo,Giuliana Falconieri Erspamer,Paolo Falaschi,Giovanna Improta,Lucia Negri,Tindaro G. Renda +7 more
TL;DR: 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.