American Society of Hirudotherapy

Leech Histamine-like Vasodilator

Histamine-receptor-acting compound — contributes to local vasodilation at feeding site.

Preclinical / mechanisticLast updated: 2026-05-26 · Reviewed by ASH Editorial Board
Molecular weight of Leech Histamine-like Vasodilator compared with other characterized leech-derived compoundsHementerin80 kDaHementin80 kDaHementin-Like Protein (HLP-1)80 kDaLeech Collagenase70 kDaHaemadipsa yanyuanensis Progr…70 kDaLeech Apyrase67 kDaCalin65 kDaHyaluronidase60 kDaAntithrombin III binding prot…58 kDaCollagenolytic Fibrinolysin55 kDaLeech Thrombospondin-Like Pro…50 kDaLeech Histamine-like Vasodila…0.2 kDa
Molecular weight (kilodaltons) of Leech Histamine-like Vasodilator (highlighted) alongside other characterized leech salivary compounds. Smaller proteins/peptides generally diffuse and act faster.

Mechanistic Evidence Box

Preclinical / mechanistic
Page type
Compound profile
Evidence type
Histamine-receptor-acting compound — contributes to local vasodilation at feeding site.
Evidence level
Mechanistic discussion
Drug vs leech
Leech-derived crude extract
Safety domains
Allergy / anaphylaxis

Clinical translation limit

Leech-derived histamine-like vasodilator activity is mechanistic only and does NOT establish any clinical therapeutic role. The histaminergic mechanism is relevant to understanding allergic/anaphylactic risk of leech application, not to claims of vasodilator efficacy.

Molecular Profile

Category
Vasodilator
Evidence tier
Preclinical
Molecular weight
200 Da
Source species
Hirudo medicinalis
Leech Histamine-like Vasodilator molecular structure

Biological Targets

  • → H1 histamine receptor

External Resources

    Related Vasodilator Compounds

    Leech Nitric Oxide Synthase Modulator

    Modulates host NOS activity at bite site — contributes to vasodilation phase of feeding.

    Leech Acetylcholine

    Cholinergic vasodilator contributing to feeding-site vascular dilation.

    Leech Bradykinin Modulator

    Salivary factor reported to modulate the bradykinin / kinin-kallikrein vasoactive cascade.

    Shuxuetong (SXT) Injection Active Peptides

    Three angiogenic peptides (DSYVGDEAQSKR, YNELRVAPEEHP, IQFLPEGSPVTM) from a leech + earthworm Shuxuetong (SXT) injection — Sun 2022 hindlimb-ischemia model.

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    This website provides educational information and does not constitute medical advice, diagnosis, or treatment recommendations. Medicinal leech therapy carries clinically meaningful risks and should be performed only by qualified clinicians under institutionally approved protocols. FDA 510(k) clearance for medicinal leeches is limited to specific indications; investigational and off-label discussions are labeled accordingly. For patient-specific guidance, consult a qualified healthcare provider.