We recorded the signals of firing Retzius neurons from Hirudo medicinalis by field-effect transistors. The axon stump of dissociated cells was attached to an open gate coated with concanavalin A. We observed a new type of neuron-transistor coupling: the extracellular voltage transients beneath the neuron were dominated by a negative peak during the rising phase of the action potential with a we...

INTRODUCTION The medicinal leech, Hirudo medicinalis, has been used in the treatment of many diseases for thousands of years. In Turkey, it is used most commonly in the management of venous diseases of lower extremities. CASE PRESENTATION A 25-year-old Turkish woman presented to our emergency room with bleeding from her left leg. She had been treated for varicose veins in her lower extremitie...

BACKGROUND Since bactericidal properties of some lysozymes are independent of their glycosidase activity, we have investigated this phenomenon for destabilase-lysozyme (DL) from medicinal leech (Hirudo medicinalis). METHODS Glycosidase activity was determined on Micrococcus luteus, non-enzymatic antibacterial activity of heat-treated DL and of synthetic peptides alpha1, alpha2 and alpha3 (fra...

The biopolymer matrigel loaded with cytokine can be used for the recruitment in vivo of specific cell populations and as a vector for the preparation of cell cultures. Data demonstrate that the injection of the matrigel biopolymer supplemented with interleukin-8 (IL-8) in the leech Hirudo medicinalis can be used to purify cell populations showing the same morphofunctional and molecular mechanis...

The regeneration pattern of two identified central neurones was studied in the leech Hirudo medicinalis. Anterior pagoda (AP) and mechanosensory touch-sensitive (T) neurones were stained in adult segmental ganglia, maintained in culture for 6-10 days. AP neurones, which normally project only to the contralateral nerve roots, sprouted extensively in all the available nerve paths during regenerat...

Pump activity is a homeostatic mechanism that maintains ionic gradients. Here we examined whether the slow reduction in excitability induced by sodium-pump activity that has been seen in many neuronal types is also involved in neuronal coding. We took intracellular recordings from a spike-bursting sensory neuron in the leech Hirudo medicinalis in response to naturalistic tactile stimuli with di...

Retzius cells of Hirudo medicinalis were cultivated on extracellular matrix protein so that extended arborizations were formed. The propagation of voltage transients along 1-microns-thick neurites was observed at a resolution of 8 microns at 10 kHz by use of a voltage-sensitive dye. Delay and width of the fluorescence transients caused by hyperpolarization of the soma are described by passive s...

We have studied the effects of tetanus toxin and botulinus toxin A on neurotransmitter release in the Retzius-->P-cell synapse of the leech and exploited the unique properties of this system, which allow for combined physiological and biochemical analyses in single-cell pairs. The sequences of Hirudo medicinalis synaptobrevin and synaptosomal-associated protein of 25 kDa (SNAP-25), deduced by c...

1. The results of perturbation experiments demonstrate the functional diversity of the interneurons (HN cells) that generate heartbeat in the medicinal leech. 2. HN cells were individually stimulated by single current pulses. The induced activity of HN cells in the first four ganglia (cell pairs HN(1)-HN(4)) reset the rhythm of the interneuron network; induced activity of those in the fifth thr...

The germinal plate of 5- to 12-day-old embryos of the leech Hirudo medicinalis consists of an anterior and a posterior sector that differ both structurally and developmentally. The posterior sector includes the five pairs of teloblasts and five paired longitudinal bandlets of stem cells and their descendant blast cells. The mesoteloblast pair and their descendant cells of the m bandlet divide s...