American Society of Hirudotherapy

Responses to mechanically and visually cued water waves in the nervous system of the medicinal leech

Research article published in The Journal of experimental biology (2018)

Last Updated: June 18, 2026Reviewed by: ASH Editorial Board
Research article — evidence reviewArticle reference
Evidence: Preclinical (animal)Clinical TrialsLehmkuhl AM et al. · The Journal of experimental biology, 2018

Abstract

Sensitivity to water waves is a key modality by which aquatic predators can detect and localize their prey. For one such predator - the medicinal leech, Hirudo verbana - behavioral responses to visual and mechanical cues from water waves are well documented. Here, we quantitatively characterized the response patterns of a multisensory interneuron, the S cell, to mechanically and visually cued water waves. As a function of frequency, the response profile of the S cell replicated key features of the behavioral prey localization profile in both visual and mechanical modalities. In terms of overall firing rate, the S cell response was not direction selective, and although the direction of spike propagation within the S cell system did follow the direction of wave propagation under certain circumstances, it is unlikely that downstream neuronal targets can use this information. Accordingly, we propose a role for the S cell in the detection of waves but not in the localization of their source. We demonstrated that neither the head brain nor the tail brain are required for the S cell to respond to visually cued water waves.

Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.

Publication typeJournal ArticleResearch Support, N.I.H., ExtramuralResearch Support, Non-U.S. Gov't
Indexed MeSH termsAnimalsCuesHirudo medicinalisMechanoreceptorsMechanotransduction, CellularNervous System Physiological PhenomenaPhotic StimulationPhotoreceptor Cells, InvertebratePredatory BehaviorWater Movements

Summary

Peer-reviewed clinical and outcomes research relevant to medicinal leech therapy and its biology. Indexed in PubMed and verified against the NCBI record.

Why This Matters for Hirudotherapy

This neurophysiology study characterized how a multisensory interneuron, the S cell, in the medicinal leech Hirudo verbana responds to mechanically and visually cued water waves, concluding the S cell encodes detection of waves (matching the prey-localization frequency profile) but is unlikely to localize the wave source, and that responses persist without the head or tail brain. This is genuine medicinal-leech biology and is relevant to hirudotherapy chiefly by deepening understanding of the organism itself (Hirudo verbana, one of the species used therapeutically) and its sensory and feeding behavior. The clear caveat is that this is basic sensory-neuroscience research on leech prey detection, not a clinical or secretome/drug-discovery study; it carries no therapeutic findings and should be framed strictly as foundational biology of the animal, not as evidence of any medical benefit.

Citation

Responses to mechanically and visually cued water waves in the nervous system of the medicinal leech.

Lehmkuhl AM et al. · The Journal of experimental biology, 2018

Added to ASH library: May 28, 2026 · Site last updated: June 18, 2026

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.