Galanin Help to Improve the Ability of Catching the Information which is Hard to be Detected

In a recent study, our lab has successfully proved that the neuron in auditory cortex of anesthetized rat increased its responses to the auditory stimulus each time after the direct local infusion of galanin, and the spontaneous firing rate was also increased each time after the infusion. In the present study we investigated whether galanin injection could draw more attention of the rats when there was weak electrical stimulus, which was the cue for indicating the right answer of the task we trained the rats to do, presenting in the auditory cortex. Rats with bilateral electrodes implanted in the auditory cortex were trained to approach the left or right hole of a behavioral apparatus to retrieve a reward depending on whether the right or left auditory cortex was electrically stimulated. After training, the rat would receive weak electrical stimulus which it could only finish correctly 70% to 80% of the task, and after that we infused galanin on both hemispheres to see if the galanin would increase the correct rate of the rat. Besides, we also investigated if infused the galanin antagonist (M40) in the same way could decrease the correct rate during the same protocol task while we controlled the correct rate before M40 infusion to about 80% to 90%. Moreover, we also used vehicle control artificial CSF (ACSF) as the control to make sure the increase or the decrease of the correct rate were the contribution of galanin or M40 infusion. What we learnt from these experiments is that the local application of galanin could help the rats to feel the electrical stimulus even when the stimulus was a little hard for the rats to notice at the first place, and also the galanin antagonist could decrease the correct rate. Our finding is that galanin is an neuropeptide which could help to activate the neuron in the auditory cortex more easily and catch the information which is too weak to pay attention to.