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Votucalis, a Novel Centrally Sparing Histamine-Binding Protein, Attenuates Histaminergic Itch and Neuropathic Pain in Mice

Lookup NU author(s): Ibrahim Alrashdi, Amal Alsubaiyel, Dr Michele Chan, Emma Battell, Dr Ilona Obara



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


Votucalis is a biologically active protein in tick (R. appendiculatus) saliva, which specifically binds histamine with high affinity and, therefore, has the potential to inhibit the host’s immunological responses at the feeding site. We hypothesized that scavenging of peripherally released endogenous histamine by Votucalis results in both anti-itch and anti-nociceptive effects. To test this hypothesis, adult male mice were subjected to histaminergic itch, as well as peripheral nerve injury that resulted in neuropathic pain. Thus, we selected models where peripherally released histamine was shown to be a key regulator. In these models, the animals received systemic (intraperitoneal, i.p.) or peripheral transdermal (subcutaneous, s.c. or intraplantar, administrations of Votucalis and itch behavior, as well as mechanical and thermal hypersensitivity, were evaluated. Selective histamine receptor antagonists were used to determine the involvement of histamine receptors in the effects produced by Votucalis. We also used the spontaneous object recognition test to confirm the centrally sparing properties of Votucalis. Our main finding shows that in histamine-dependent itch and neuropathic pain models peripheral (s.c. or administration of Votucalis displayed a longer duration of action for a lower dose range, when compared with Votucalis systemic (i.p.) effects. Stronger anti-itch effect was observed after co-administration of Votucalis (s.c.) and antagonists that inhibited peripheral histamine H1 and H2 receptors as well as central histamine H4 receptors indicating the importance of these histamine receptors in itch. In neuropathic mice, Votucalis produced a potent and complete anti-nociceptive effect on mechanical hypersensitivity, while thermal (heat) hypersensitivity was largely unaffected. Overall, our findings further emphasize the key role for histamine in the regulation of histaminergic itch and chronic neuropathic pain. Given the effectiveness of Votucalis after peripheral transdermal administration, with a lack of central effects, we provide here the first evidence that scavenging of peripherally released histamine by Votucalis may represent a novel therapeutically effective and safe long-term strategy for the management of these refractory health conditions.

Publication metadata

Author(s): Alrashdi I, Alsubaiyel A, Chan M, Battell EE, Ennaceur A, Nunn MA, Weston-Davies W, Chazot PL, Obara I

Publication type: Article

Publication status: Published

Journal: Frontiers in Pharmacology

Year: 2022

Volume: 13

Print publication date: 29/03/2022

Online publication date: 08/03/2022

Acceptance date: 15/02/2022

Date deposited: 10/03/2022

ISSN (print): 0340-465X

ISSN (electronic): 1663-9812

Publisher: Frontiers Research Foundation


DOI: 10.3389/fphar.2022.846683


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