title: Catecholaminergic innervation of central and peripheral auditory circuitry varies with reproductive state in female midshipman fish, Porichthys notatus.
abstract: In seasonal breeding vertebrates, hormone regulation of catecholamines, which include dopamine and noradrenaline, may function, in part, to modulate behavioral responses to conspecific vocalizations. However, natural seasonal changes in catecholamine innervation of auditory nuclei is largely unexplored, especially in the peripheral auditory system, where encoding of social acoustic stimuli is initiated. The plainfin midshipman fish, Porichthys notatus, has proven to be an excellent model to explore mechanisms underlying seasonal peripheral auditory plasticity related to reproductive social behavior. Recently, we demonstrated robust catecholaminergic (CA) innervation throughout the auditory system in midshipman. Most notably, dopaminergic neurons in the diencephalon have widespread projections to auditory circuitry including direct innervation of the saccule, the main endorgan of hearing, and the cholinergic octavolateralis efferent nucleus (OE) which also projects to the inner ear. Here, we tested the hypothesis that gravid, reproductive summer females show differential CA innervation of the auditory system compared to non-reproductive winter females. We utilized quantitative immunofluorescence to measure tyrosine hydroxylase immunoreactive (TH-ir) fiber density throughout central auditory nuclei and the sensory epithelium of the saccule. Reproductive females exhibited greater density of TH-ir innervation in two forebrain areas including the auditory thalamus and greater density of TH-ir on somata and dendrites of the OE. In contrast, non-reproductive females had greater numbers of TH-ir terminals in the saccule and greater TH-ir fiber density in a region of the auditory hindbrain as well as greater numbers of TH-ir neurons in the preoptic area. These data provide evidence that catecholamines may function, in part, to seasonally modulate the sensitivity of the inner ear and, in turn, the appropriate behavioral response to reproductive acoustic signals.
authors: Department of Biology, Brooklyn College, City University of New York, Brooklyn, NY, United States of America; Program in Neuroscience, City University of New York, New York, NY, United States of America; Program in Ecology, Evolutionary Biology and Behavior, City University of New York, New York, NY, United States of America; Program in Behavioral and Cognitive Neuroscience, The Graduate Center, City University of New York, New York, NY, United States of America; Aquatic Research and Environmental Assessment Center, Brooklyn College, Brooklyn, NY, United States of America.
authors: Paul M
authors: PM
authors: Forlano
authors: Department of Biology, Brooklyn College, City University of New York, Brooklyn, NY, United States of America; Program in Ecology, Evolutionary Biology and Behavior, City University of New York, New York, NY, United States of America.
authors: Zachary N
authors: ZN
authors: Ghahramani
authors: Department of Biology, Brooklyn College, City University of New York, Brooklyn, NY, United States of America.
authors: Camillia M
authors: CM
authors: Monestime
authors: Department of Biology, Brooklyn College, City University of New York, Brooklyn, NY, United States of America.
authors: Philip
authors: P
authors: Kurochkin
authors: Department of Biology, Brooklyn College, City University of New York, Brooklyn, NY, United States of America.
authors: Alena
authors: A
authors: Chernenko
authors: Department of Biology, Brooklyn College, City University of New York, Brooklyn, NY, United States of America.
authors: Dmitriy
authors: D
authors: Milkis
mesh_terms: D000818:Animals; D024541:Batrachoidiformes / Q000033:anatomy & histology / Q000502:physiology*; D001522:Behavior, Animal / Q000502:physiology; D004027:Diencephalon / Q000033:anatomy & histology / Q000502:physiology*; D059290:Dopaminergic Neurons / Q000166:cytology / Q000502:physiology*; D007758:Ear, Inner / Q000033:anatomy & histology / Q000294:innervation* / Q000502:physiology*; D005260:Female; D012098:Reproduction / Q000502:physiology; D012919:Social Behavior