Serotonergic modulation of crayfish hindgut.
The crayfish hindgut is a morphologically differentiated tube that varies along its length in the distribution of muscles and glands, contractile properties, serotonergic innervation, patterns of 5-HT receptor expression, and sensitivity to serotonin (5-HT). Anatomical differences divide the hindgut into five distinct segments along its length. Spontaneous pulsatile contractions produced by the isolated hindgut decrease in force and increase in frequency along the anterior-posterior axis. Central input to the hindgut comes from a large cluster of 5-HT-immunoreactive neurons in the terminal abdominal ganglion that form a large nerve plexus on the hindgut. 5-HT(1alpha) and 5-HT(2beta) receptors vary in their distribution along the hindgut, and are associated with longitudinal and circular muscles and with axon collaterals of the 5-HT-immunoreactive neurons. Application of 30 nmol l(-1) to 1 mumol l(-1) 5-HT to rostral, middle, or caudal sections of hindgut produced tension changes that varied with the concentration and section. 5-HT also initiated antiperistaltic waves in the posterior hindgut. These results indicate that 5-HT is an important neuromodulator for initiating contractions and coordinating activity in the different functional compartments along the rostral-to-caudal axis of the hindgut.
Musolf
Barbara E
BE
Neuroscience Institute, Georgia State University, Atlanta, Georgia 30302-5030, USA.
Spitzer
Nadja
N
Antonsen
Brian L
BL
Edwards
Donald H
DH
D000818:Animals; D003400:Astacoidea / Q000502:physiology*; D004064:Digestive System / Q000187:drug effects*; D009129:Muscle Tonus / Q000187:drug effects; D010528:Peristalsis / Q000187:drug effects; D012701:Serotonin / Q000494:pharmacology*; D012702:Serotonin Antagonists / Q000494:pharmacology*
D012702:Serotonin Antagonists; D012701:Serotonin