Monoamines and neuropeptides as transmitters in the sedentary polychaete Sabellastarte magnifica: actions on the longitudinal muscle of the body wall.
Pharmacological studies on the body wall musculature of the sedentary polychaete Sabellastarte magnifica show a potential neurotransmitter role for monoamines and neuropeptides in this organism. All catecholamines induced contraction of longitudinal muscle strips, while serotonin and the neuropeptides FMRFamide and substance P caused a relaxation of both resting and active muscle. In addition, we demonstrate catecholaminergic and serotonergic pathways in the nervous system of this sabellid, using immunohistochemistry and catecholamine-induced fluorescence. The presence of neuropeptide-containing fibers in the nervous system of this polychaete has been previously reported. Together these results suggest that catecholamines act as excitatory transmitters on the longitudinal muscle cells of the body wall of S. magnifica, while serotonin and FMRFamide, and possible substance P, are inhibitory transmitters. The possibility of coexistence of serotonin and FMRFamide within the same neuronal cell bodies and fibers of this polychaete is also explored.
Department of Biology, University of Puerto Rico, Río Piedras 00931.
L
L
Díaz-Miranda
G E
GE
de Motta
J E
JE
García-Arrarás
D000595:Amino Acid Sequence; D000818:Animals; D015306:Biogenic Monoamines / Q000378:metabolism / Q000502:physiology*; D002490:Central Nervous System / Q000378:metabolism; D004298:Dopamine / Q000502:physiology; D019835:FMRFamide; D005455:Fluorescent Antibody Technique; D006651:Histocytochemistry; D007447:Invertebrate Hormones / Q000502:physiology; D008969:Molecular Sequence Data; D009132:Muscles / Q000502:physiology*; D009479:Neuropeptides / Q000378:metabolism / Q000502:physiology*; D018377:Neurotransmitter Agents / Q000378:metabolism / Q000502:physiology*; D010525:Peripheral Nerves / Q000378:metabolism; D011077:Polychaeta / Q000378:metabolism / Q000502:physiology*; D012701:Serotonin / Q000502:physiology
D015306:Biogenic Monoamines; D007447:Invertebrate Hormones; D009479:Neuropeptides; D018377:Neurotransmitter Agents; D012701:Serotonin; D019835:FMRFamide; D004298:Dopamine