XXXX suppresses excitability of visual-processing neurons in the optic tectum.

@entity1176 @entity57391
UNASSIGNED: Animals change their behavior in response to sensory cues in the environment as well as their physiological status. For example, it is generally accepted that their sexual behavior is modulated according to seasonal environmental changes or the individual's maturational/reproductive status, and neuropeptides have been suggested to play important roles in this process. Some behavioral modulation arises from neuropeptide modulation of sensory information processing in the central nervous system, but the neural mechanisms still remain unknown. Here, we focused on the neural basis of neuropeptide modulation of visual processing in vertebrates. The terminal nerve neurons that contain gonadotropin releasing hormone 3 (TN- @entity57391 neurons) are suggested to modulate reproductive behavior and have massive projections to the optic tectum (OT), which plays an important role in visual processing. In the present study, to examine whether @entity57391 modulates retino-tectal neurotransmission in the OT, we analyzed the effect of @entity57391 electrophysiologically and morphologically. We found that field potentials evoked by optic tract fiber stimulation, which represent the retino-tectal neurotransmission, were modulated postsynaptically by @entity57391 . Whole-cell recording from the postsynaptic neurons in the retino-tectal pathway suggested that @entity57391 activates BK channels and thereby suppresses the membrane excitability. Furthermore, our improved morphological analysis using fluorescently labeled @entity1176 peptides showed that @entity1176 receptors are localized mainly around the cell bodies of the postsynaptic neurons. Our results indicate that TN- @entity57391 neurons modulate the retino-tectal neurotransmission by suppressing the excitability of projection neurons in the OT, which underlies the neuromodulation of behaviorally relevant visual information processing by the neuropeptide @entity57391 .
