Ongoing research Field and Laboratory methods Prey, predators and parasites Anatomy and Morphology Venom Details and Pictures Medical Usage Geographical Range Scorpions in Captivity Reproductive behavior Myths and Legends General Features

Neuromuscular test
Considerations

1. Venom has been known to be a powerful neurotoxin which affects the normal functioning of the nerves. We would like to test if nerves are indeed affected, by observing the muscle to which a nerve is attached. If the muscular contractions decrease, this would mean a decrease in nervous activity as well, which then can mean a reduction in the sensation of pain.

Objectives

· To investigate the effect of crude H.longimanus venom on nervous activity.

· To test for reversibility of the effect of the venom on vervous activity.

Aparatus

MacLab Recording System

Organ Bath Setup

Procedures:

1. The muscles were placed in the organ bath(Appendix 11.9). The muscle was tied on the lower end to the electrode hook, and the muscle was passed through two platinum electrodes that were connected to the electrical stimulator. The upper end of the muscle was tied and attached to the transducer, which was, in turn, connected to the MacLab Recording System.

2. The muscle was electrically stimulated, and the twitches (contractions) made by the muscle were recorded on the graphs overleaf.

Conclusions and discussion

CONCLUSIONS:

4. Crude scorpion (H.longimanus) venom produced a high tension and reduced contraction of the rat anococcygeus muscle.

5. The effects of the venom on the muscle was reversible, as the amplitude of contraction of muscle in both graphs before treatment and after flushing out of venom was almost the same.

DISCUSSION :

6. Crude scorpion (Heterometrus longimanus) venom produced a marked contraction of the muscle when added to the organ bath. In Graph 5.1, interval

2 showed a high tension occurring in the muscle when crude venom was added. This can be seen in the increased baseline of the graph in Interval 2, when it was at 5.5g, as compared to interval 1, when it was about -1.8g. The amplitude of the contractions in interval 2 was also greatly reduced as compared to the normal contraction of rat anococcygeous muscle as shown in interval 1.

7. The reduced amplitude in contractions suggest a less vigorous contraction.

8. As the electrodes were connected directly to the motor neurones which were in turn connected to the muscle itself, we can hypothesize that the venom has in fact affected neural transmissions in the nerves. When neural transmissions are blocked, the muscles would theoretically show a less dramatic contraction.