HSE-HA Rodent Shocker

Cerebral seizures can be induced using constant sinusoidal alternating current to determine the effect of anticonvulsant drugs.  For the reliable induction of seizures it is necessary to achieve satisfactory current flow.  The standard version of the rodent shocker is typically paired with the ear electrodes which have a higher resistance.  The low current version of the shocker is often used with eye electrodes or when lower stimulation intensity or more precise current control is required.

Stimulation Electrodes

The electrodes are not included with the shocker and must be purchased separately (73-0107 or 73-0108).

There are two types of shock stimulation electrodes for applying electric shock to mice and rats for testing anticonvulsant drugs: Eye electrodes and (especially for mice) ear electrodes.

Ear Electrodes

The ear electrodes offer the advantage that the course of the seizure can be observed more clearly but have the disadvantage of a larger contact resistance.  It is important that the electrodes are properly moistened!  Normally the output circuit for constant current ensures the required stimulus response even for different impedances (a.c. resistances) of the animal tested.

The ear electrodes consist of two -insulated nickel-plated clips.  The contact points are formed by two chlorided silver discs 6 mm diameter and 1 mm thick.

This type of application requires a larger shock energy since the contact resistance to the tissue is relatively high even when the skin is moistened.

EyeElectrodes

The eye electrodes are bipolar.  Each forcep end has a stainless steel button covered by thin leather pad. The leather pad must be moistened with saline solution or electrode gel prior to use.  A lower shock energy is required since the eye is a highly conductive point.

Stimulation Current

The stimulation voltage is increased inside the unit until the selected stimulation current is produced. After electrical stimulation the delivered current is displayed. The stimulus duration can also be preset between 0.1 to 9.9 seconds and the elapsed time is monitored on a bargraph (line of LEDs).

Safety

The stimuli produced are not without danger to the operator.  With an open output circuit (no animal connected to the unit) the stimulation voltage can reach its maximum of 750 Volt.  In order to ensure operator safety the stimulus can only be triggered when two separate buttons ‘RELEASE’ (unblocking the inhibit circuit) and ‘START‘ are operated in sequence.  In addition, the stimulus output is floating and has no connection to ground.  The current can flow only between the two electrodes!  As a further safety feature the output is automatically switched off if the electrodes are not connected to an object or if the contact between electrode and tissue is interrupted during stimulation.

To increase the stimulation current the CURRENT SETTING button is pressed and the control to the right of it rotated to obtain the required stimulation current.

Rubber gloves must be worn when working with the unit.

The output sockets are protected against contact.  Only HSE shock electrodes with the original Yellow HSE safety banana plugs must be used.

Foot switch

A foot switch is supplied for triggering the stimulus; when working with the eye electrode one hand is used to hold the animal while the other holds the flexible forceps-shaped eye electrode.