TY - JOUR
T1 - Serotonin elicits long-lasting enhancement of rhythmic respiratory activity in turtle brain stems in vitro
AU - Johnson, Stephen M.
AU - Wilkerson, Julia E R
AU - Henderson, Daniel R.
AU - Wenninger, Michael R.
AU - Mitchell, Gordon S.
PY - 2001
Y1 - 2001
N2 - Brain stem preparations from adult turtles were used to determine how bath-applied serotonin (5-HT) alters respiration-related hypoglossal activity in a mature vertebrate. 5-HT (5-20 μM) reversibly decreased integrated burst amplitude by ∼45% (P < 0.05); burst frequency decreased in a dose-dependent manner with 20 μM abolishing bursts in 9 of 13 preparations (P < 0.05). These 5-HT-dependent effects were mimicked by application of a 5-HT1A agonist, but not a 5-HT1B agonist, and were abolished by the broad-spectrum 5-HT antagonist, methiothepin. During 5-HT (20 μM) washout, frequency rebounded to levels above the original baseline for 40 min (P < 0.05) and remained above baseline for 2 h. A 5-HT3 antagonist (tropesitron) blocked the post-5-HT rebound and persistent frequency increase. A 5-HT3 agonist (phenylbiguanide) increased frequency during and after bath application (P < 0.05). When phenylbiguanide was applied to the brain stem of brain stem/spinal cord preparations, there was a persistent frequency increase (P < 0.05), but neither spinal-expiratory nor -inspiratory burst amplitude were altered. The 5-HT3 receptor-dependent persistent frequency increase represents a unique model of plasticity in vertebrate rhythm generation.
AB - Brain stem preparations from adult turtles were used to determine how bath-applied serotonin (5-HT) alters respiration-related hypoglossal activity in a mature vertebrate. 5-HT (5-20 μM) reversibly decreased integrated burst amplitude by ∼45% (P < 0.05); burst frequency decreased in a dose-dependent manner with 20 μM abolishing bursts in 9 of 13 preparations (P < 0.05). These 5-HT-dependent effects were mimicked by application of a 5-HT1A agonist, but not a 5-HT1B agonist, and were abolished by the broad-spectrum 5-HT antagonist, methiothepin. During 5-HT (20 μM) washout, frequency rebounded to levels above the original baseline for 40 min (P < 0.05) and remained above baseline for 2 h. A 5-HT3 antagonist (tropesitron) blocked the post-5-HT rebound and persistent frequency increase. A 5-HT3 agonist (phenylbiguanide) increased frequency during and after bath application (P < 0.05). When phenylbiguanide was applied to the brain stem of brain stem/spinal cord preparations, there was a persistent frequency increase (P < 0.05), but neither spinal-expiratory nor -inspiratory burst amplitude were altered. The 5-HT3 receptor-dependent persistent frequency increase represents a unique model of plasticity in vertebrate rhythm generation.
KW - 5-Hydroxytryptamine
KW - Control of breathing
KW - Plasticity
KW - Reptile
KW - Respiratory control
KW - Rhythm generation
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U2 - 10.1152/jappl.2001.91.6.2703
DO - 10.1152/jappl.2001.91.6.2703
M3 - Article
C2 - 11717237
AN - SCOPUS:0035178971
SN - 8750-7587
VL - 91
SP - 2703
EP - 2712
JO - Journal of applied physiology
JF - Journal of applied physiology
IS - 6
ER -