Interest in potential agricultural and medical uses of spider venom is largely due to its selectivity in species and site of action. Current research centres around exploring the development of pesticides and drugs for treating cardiac patients.
Components in the neurotoxic venom of an Australian funnel-web spider have been found to be specific for insects such as cockroaches, crickets, fruit-flies and the Helicoverpa armigera moth which destroys cotton crops. Targeting specific species prevents the accidental killing of other insects. This selectivity also means that the pesticide is harmless to other organisms so there would be no danger if it entered the food chain. The compounds in venom are environmentally friendly and the development of resistance to a spider venom pesticide would be slow. Traditional chemical pesticides do not tend to be species specific, are toxic to humans in large amounts and insects develop resistance towards them relatively fast so it is easy to see why pesticides based on spider venom are attractive.
Prevention of Atrial Fibrillation
The venom of the Chile Rose tarantula (Grammostola spatulata) from South America contains an active protein, GsMtx-4, which blocks ion channels that are stretch activated. These channels are therefore sensitive to muscle contraction and blood pressure and play an important role in co-ordinating a heartbeat. A heart attack causes these ion channels to open and release chemicals which interfere with the heart rhythm leading to atrial fibrillation. Fibrillation is when the upper heart chambers (the atria) contract rapidly and prevent sufficient blood from entering the lower chambers (the venticles). It is fibrillation which often causes the death of a heart attack victim, not the attack itself so GsMtx-4 could be utilised in a potentially life-saving drug which prevents fibrillation. GsMtx-4 is ineffective on the normal unstretched heart so side effects should be small or even non-existent. The venom from the Chile Rose spider is also harmless to humans which constitutes an extra safety precaution.
Prevention of Brain Damage
Oxygen deprivation caused by events such as stroke or excessive smoke inhalation can result in nerve cell damage in the brain. Glutamate is a neurotransmitter in the human brain and large amounts of it are released by these damaged neurons causing the death of neighbouring nerve cells. The Holena curta funnel-web spider produces a venom containing the active ingredient HF-7 which blocks receptors on the nerve cell membranes and prevents glutamate production. A drug developed using this compound could therefore limit brain damage for stroke victims.