Most pet owners have probably seen their furry friends get soaking wet. After dripping for 1 second, they spray water everywhere. wet dog shake. Almost all hairy mammals, from dogs, cats, and mice to lions, tigers, and bears, shiver and dry when their fur gets wet. But even though it's common for dogs to get wet and shiver, scientists still don't know what causes this behavior.
Our skin is very sensitive to touch. Most people can easily distinguish the gentle touch of a loved one, a breeze, the movement of a pest on the skin. We sense touch through our nervous system using specialized cells called . somatosensory neurons Detect changes in our skin. Hairy animals have 12 unique types of somatosensory neurons that sense and respond to touch. One such neuron is C-LTMRresponds only to mild, slow stimuli. When these neurons sense something, they react strongly by sending strong electrical signals through the nervous system. The research team wondered if these neurons were responsible for the tremors in wet dogs.
To investigate the link between C-LTMR neurons and wet dog tremors, the researchers first measured this behavior in mice. They used a dropper to place droplets of sunflower seed oil on the necks of 10 mice and monitored their behavior for five minutes. Mice initiated wet dog shaking within an average of 10 seconds after droplet placement, often 3 to 4 times every 18 seconds. After the first minute, the mice stopped shaking frequently and instead groomed and scratched themselves.
So the researchers wanted to know whether the shivering in wet dogs was an automatic behavior triggered by neurons that sensed these droplets. To test this, they used genetic engineering techniques. crisper In order to remove the genes that create touch sensors in neurons, piezo 2. CRISPR is piezo 2 Gene for finding mouse cells themselves piezo 2 gene. CRISPR then disrupts the gene, preventing the mouse cells from making touch sensors. When researchers placed oil drops on the necks of genetically engineered mice, wet dog shakes did not occur. The researchers concluded that touch is the main mechanism that triggers the automatic shivering behavior in wet dogs.
Many somatosensory neurons use Piezo2 to sense touch, so the researchers are unable to pinpoint the neurons responsible for the wet dog's tremors. However, some genes are only produced by certain types of neurons. The researchers used genetic engineering to target these genes, a process called light-sensitization. optogenetics. These light-sensitive genes produce proteins that become activated when scientists shine a blue laser on them. The researchers used optogenetics to create light-sensitive C-LTMR neurons and compared them to other light-sensitive somatosensory neurons.
When the researchers shined a light on the skin of seven light-sensitive C-LTMR mice, the mice shivered 60% of the time like a wet dog. But mice with other light-sensitive neurons did not show the dog-wetting tremors in response to the laser. The researchers found that photosensitive C-LTMR mice responded best 80% of the time when the laser was applied to the neck rather than the back or thighs, with 30% and 0% responses, respectively. Ta.
The researchers thought this might indicate that C-LTMR neurons were sending signals through other neurons in the spine. spinal parabrachial neurons or SPN. To test this, the researchers cultured SPNs containing optogenetic C-LTMR neurons in Petri dishes. When they shined a laser on C-LTMR neurons, the electrical signals within the SPN were measured with electrodes, showing that these neurons were communicating.
The researchers concluded that wet dog tremors are caused specifically by C-LTMR neurons in the spine. They hope that future studies can build on their findings and gain a deeper understanding of the connections between C-LTMR neurons and the brain. Continuing these studies will impact how scientists understand wet dog tremors in mammals and how hypersensitivity and other contact-based symptoms develop in humans. Possibly.
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Source: sciworthy.com
