a computer simulation of experiments which may be performed on the superior cervical ganglion-nictitating membrane preparation of the cat in vivo

David Dewhurst and Jake Broadhurst

An interactive, menu driven program which simulates experiments on the superior cervical ganglion-nictitating membrane preparation of the cat (in vivo) to teach the pharmacology of ganglionic transmission and sympathetically innervated smooth muscle.

Introduction: provides information about the program and it's curricula context;

Tutorial: presents diagrammatic representations of the effector junction and the superior cervical ganglion. This section of the program uses animated sequences to demonstrate the stages of transmission at both the synapse and neuroeffector junction and highlights possible sites of action of drugs;

Methods: describes the preparation, protocols for nerve stimulation and administration of drugs to the superior cervical ganglion and the nictitating membrane, and the method of recording contractions of the nictitating membrane.

Experiments: allows students to perform simulated experiments on the preparation and provides recordings of the force of contraction of both ipsilateral and contralateral nictitating membranes which are displayed on a screen designed to emulate a chart recorder. A sub-menu gives students some control over experimental parameters (they can choose: 1. to administer an agent from a list: saline (vehicle control), acetylcholine, noradrenaline, atropine, phentolamine, propranolol, isoprenaline, hexamethonium, physostigmine, nicotine (low and high dose), tyramine, an unknown (which is randomly selected from the list above when the program is run); 2. the site of administration; 3. whether to electrically stimulate preganglionic nerves (half-maximal stimulation).

Although it is envisaged that the tutor will develop a set of tasks for students to address when using the simulation which will meet their own teaching objectives, this section does also includes some suggested tasks to aid independent use of the program.

Review of Cat Nictitating Membrane

Click on one of the above screen grabs to see full size image.