What are Ning's chances of success

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"Toothache is a horror for many people, and hypersensitive teeth are no less stressful," says Prof. Dr. Katharina Zimmermann from the Anaesthesiological Clinic of the Erlangen University Hospital at FAU. "Anyone who likes to eat ice cream and has sensitive teeth knows the problem: As soon as the ice cream touches the tooth, lightning strikes."

The cold sensor lies directly on the odontoblasts

Responsible for this is the body's own mechanism that protects human teeth from overload. “Nature has installed the strongest protective reflex in the body in the teeth,” explains the FAU pain researcher. "Because teeth don't heal if they break." The reflex therefore protects the pulp and the sensitive cells of the tooth tissue, the so-called odontoblasts. These form the hard substance of the tooth, i.e. the dentin and the tooth enamel.

The odontoblasts also function as cold sensors, as the research team has now demonstrated for the first time. The TRPC5 ion channel, which acts as a cold receptor, is located directly on the processes of the odontoblasts. Ion channels are pores in cell membranes that act like molecular sphincters. After detecting a signal, such as a change in temperature, the channels open and allow ions to flow into the cell. This creates an electrical impulse that is passed on to convey information.

“The cell body of the odontoblasts and their nerve endings are located on the outer edge of the tooth pulp,” explains Professor Zimmermann. "They have a process that runs in a fine canal in the dentin, where it measures the temperature changes and transmits them electrically to the brain, thus triggering the painful reaction."

Starting point for remedies for toothache

The FAU researcher was previously involved in the discovery of the cold sensitivity of the TRPC5 ion channel. “We have now found out that the same ion channel is responsible for the sensation of cold in teeth. This is an excellent starting point for future remedies against toothache and teeth that are hypersensitive to cold. ”Since the receptor in the tooth is found on the specialized sensory cells and less on the nerves, the team at the anesthesiological clinic suspects that the usual side effects of a conduction anesthesia, such as numbness and paralysis in the jaw area , will not happen. The researchers also found an explanation for the mechanism of action of an ancient home remedy for toothache: the main component of clove oil is eugenol - and it blocks the TRPC5 receptor.

Mechanism of sensitivity to cold deciphered

The scientists have deciphered this mechanism of sensitivity to cold through experiments on mouse teeth. The research team developed a new method of registering electrical impulses from the dental nerves of intact mouse teeth. "Using a special technique with glass electrodes, I was able to compare normal mice with mice that lacked the TRPC5 molecule," explains electrophysiologist Dr. Laura Bernal (now Universidad Alcalá in Spain). “It turned out that TRPC5 is crucial for a large part of the cold responses in the tooth and that TRPC5 antagonists block the cold responses.” In behavioral tests on mice, FAU researcher Dr. Christine König finally found that the mice that lack the TRPC5 receptor no longer develop toothache after a tooth infection. People with cold-sensitive teeth can now also hope for this, because the team found a particularly large number of TRPC5 receptors in inflamed teeth with caries.