Distinct Modes of Presynaptic Inhibition of Cutaneous Afferents and Their Functions in Behavior.

ABSTRACT: Presynaptic inhibition (PSI) of primary sensory neurons is implicated in controlling gain and acuity in sensory systems. Here, we define circuit mechanisms and functions of PSI of cutaneous somatosensory neuron inputs to the spinal cord. We observed that PSI can be evoked by different sensory neuron populations and mediated through at least two distinct dorsal horn circuit mechanisms. Low-threshold cutaneous afferents evoke a GABA_A-receptor-dependent form of PSI that inhibits similar afferent subtypes, whereas small-diameter afferents predominantly evoke an NMDA-receptor-dependent form of PSI that inhibits large-diameter fibers. Behaviorally, loss of either GABA_A receptors (GABA_ARs) or NMDA receptors (NMDARs) in primary afferents leads to tactile hypersensi

SUBMITTER: Zimmerman AL 

PROVIDER: S-EPMC6472967 | biostudies-literature | 2019 Apr

REPOSITORIES: biostudies-literature