TY - JOUR
T1 - Dopamine modulates the activity of sensory hair cells
AU - Toro, Cecilia
AU - Trapani, Josef G.
AU - Pacentine, Itallia
AU - Maeda, Reo
AU - Sheets, Lavinia
AU - Mo, Weike
AU - Nicolson, Teresa
N1 - Publisher Copyright:
© 2015 the authors.
PY - 2015/12/16
Y1 - 2015/12/16
N2 - The senses of hearing and balance are subject to modulation by efferent signaling, including the release of dopamine (DA). How DA influences the activity of the auditory and vestibular systems and its site of action are not well understood. Here we show that dopami-nergic efferent fibers innervate the acousticolateralis epithelium of the zebrafish during development but do not directly form synapses with hair cells. However, a member of the D1-like receptor family, D1b, tightly localizes to ribbon synapses in inner ear and lateral-line hair cells. To assess modulation of hair-cell activity, we reversibly activated or inhibited D1-like receptors (D1Rs) in lateral-line hair cells. In extracellular recordings from hair cells, we observed that D1R agonist SKF-38393 increased microphonic potentials, whereas D1R antagonist SCH-23390 decreased microphonic potentials. Using ratiometric calcium imaging, we found that increased D1R activity resulted in larger calcium transients in hair cells. The increase of intracellular calcium requires Cav1.3a channels, as a Cav1 calcium channel antagonist, isradipine, blocked the increase in calcium transients elicited by the agonist SKF-38393. Collectively, our results suggest that DA is released in a paracrine fashion and acts at ribbon synapses, likely enhancing the activity of presynaptic Cav1.3a channels and thereby increasing neurotransmission.
AB - The senses of hearing and balance are subject to modulation by efferent signaling, including the release of dopamine (DA). How DA influences the activity of the auditory and vestibular systems and its site of action are not well understood. Here we show that dopami-nergic efferent fibers innervate the acousticolateralis epithelium of the zebrafish during development but do not directly form synapses with hair cells. However, a member of the D1-like receptor family, D1b, tightly localizes to ribbon synapses in inner ear and lateral-line hair cells. To assess modulation of hair-cell activity, we reversibly activated or inhibited D1-like receptors (D1Rs) in lateral-line hair cells. In extracellular recordings from hair cells, we observed that D1R agonist SKF-38393 increased microphonic potentials, whereas D1R antagonist SCH-23390 decreased microphonic potentials. Using ratiometric calcium imaging, we found that increased D1R activity resulted in larger calcium transients in hair cells. The increase of intracellular calcium requires Cav1.3a channels, as a Cav1 calcium channel antagonist, isradipine, blocked the increase in calcium transients elicited by the agonist SKF-38393. Collectively, our results suggest that DA is released in a paracrine fashion and acts at ribbon synapses, likely enhancing the activity of presynaptic Cav1.3a channels and thereby increasing neurotransmission.
KW - D1 receptor
KW - Dopamine
KW - Efferents
KW - Hair cell
KW - Lateral-line organ
KW - Zebrafish
UR - http://www.scopus.com/inward/record.url?scp=84949989291&partnerID=8YFLogxK
U2 - 10.1523/JNEUROSCI.1691-15.2015
DO - 10.1523/JNEUROSCI.1691-15.2015
M3 - Article
C2 - 26674873
AN - SCOPUS:84949989291
SN - 0270-6474
VL - 35
SP - 16494
EP - 16503
JO - Journal of Neuroscience
JF - Journal of Neuroscience
IS - 50
ER -