Giant spider promises to ease irritable bowel syndrome pain

Molecules from the venom of one of the world’s largest spiders could help researchers led by the University of Queensland tailor pain blockers for people with irritable bowel syndrome (IBS).

The researchers examined 28 spiders, and venom from the Venezuelan Goliath Pie Rosada tarantula, which has a leg length of up to 30 centimeters, showed the most promise.

The team led by Professor Richard Lewis from the UQ Institute for Molecular Bioscience in collaboration with Professor Stuart Brierley from Flinders University and the South Australian Health and Medical Research Institute hopes to find effective pain relief for the chronic intestinal pain.

“All pain is complex, but intestinal pain is particularly difficult to treat and affects about 20 percent of the world’s population,” said Professor Lewis.

“Current medications fail to produce effective pain relief in many patients before side effects limit the dose that can be administered.” Professor Brierley said that IBS and other gastrointestinal and bladder disorders cause chronic visceral pain, pain that affects internal organs.

“Internal organs have a complex network of sensory nerves that have a wide range of voltage-gated ion channels and receptors to detect stimuli,” he said.

“The hypersensitivity of these nerves in disease often contributes to the development of pain.”

Voltage-gated ion channels open and close in response to changes in the cell membrane, and their dysfunction is identified as a cause of chronic visceral pain.

Professor Lewis said that spider venoms contain hundreds of mini proteins known as peptides that can inhibit the opening of voltage-gated ion channels.

“Unfortunately, these peptides are not completely selective for pain targets,” he said.

“Our goal was to find more specialized pain blockers that are potent and target sodium pain channels for chronic visceral pain, but not those that are active in the heart and other channels.”

The team found that two peptides isolated from tarantula venom inhibited the most important ion channels underlying pain, one particularly potent in reducing sensory nerves in the bladder and colon and nearly stopping chronic visceral pain in an IBS model.

“We now have a really strong understanding of the structure and function of these spider venom peptides,” said Professor Lewis.

“Highly selective ones have potential as pain treatments, while others are useful as new research tools to enable us to understand the underlying factors of pain in different diseases.”