15 research outputs found
Serotonin and neuropeptide FMRFamide in the attachment organs of trematodes
The serotoninergic and FMRFamidergic nervous system of the attachment organs of trematodes were examined using immunocytochemical techniques and confocal scanning laser microscopy. Adult trematodes from eight families as well as cercariae and metacercariae from ten families were studied. TRITC-conjugated phalloidin was used to stain the muscle fibres. The serotonin- and FMRFamide-immunoreactive (IR) nerve cells and fibres were revealed to be near the muscle fibres of the oral and ventral suckers of the trematodes and their larvae. The results indicate the important role of neurotransmitters, serotonin and neuropeptide FMRFamide in the regulation of muscle activity in the attachment organs of trematodes and can be considered in perspective for the development of new anthelmintic drugs, which can interrupt the function of the attachment organs of the parasites
Effects of FMFRamide-related peptides and neuropeptide F on planarian regeneration (Platyhelminthes, Tricladida)
Effects of monoamine manipulations on the personality and gene expression of three-spined sticklebacks
Among-individual behavioral differences (i.e. animal personality) are commonly observed across taxa, although the underlying, causal mechanisms of such differences are poorly understood. Animal personality has been correlated with physiological functions as well as fitness-related traits. Variation in many aspects of monoamine systems, such as metabolite levels and gene polymorphisms, has been linked to behavioral variation. Therefore, here we experimentally investigated the potential role of monoamines in explaining individual variation in personality, using two common pharmaceuticals that respectively alter the levels of serotonin and dopamine in the brain: fluoxetine and ropinirole. We exposed three-spined sticklebacks, a species that shows animal personality, to either chemical alone or to a combination of the two chemicals, for 18 days. During the experiment, fish were assayed at four time points for the following personality traits: exploration, boldness, aggression and sociability. To quantify brain gene expression on short- and longer-term scales, fish were sampled at two time points. Our results show that monoamine manipulations influence fish behavior. Specifically, fish exposed to either fluoxetine or ropinirole were significantly bolder, and fish exposed to the two chemicals together tended to be bolder than control fish. Our monoamine manipulations did not alter the gene expression of monoamine or stress-associated neurotransmitter genes, but control, untreated fish showed covariation between gene expression and behavior. Specifically, exploration and boldness were predicted by genes in the dopaminergic, serotonergic and stress pathways, and sociability was predicted by genes in the dopaminergic and stress pathways. These results add further support to the links between monoaminergic systems and personality, and show that exposure to monoamines can causally alter animal personality.Funding agencies: Linkopings Universitet Centre for Systems Neurobiology; Royal Swedish Academy of Sciences (Kungl. Vetenskapsakademien); Royal Physiographic Society of Lund (Kungl. Fysiografiska Sallskapet i Lund); Langmanska Cultural Foundation (Langmanska Kulturfonden);</p
Physiological effects of FMRFamide-related peptides and classical transmitters on dispersed muscle fibres of the turbellarian, Procerodes littoralis.
The physiological effects of selected classical transmitters and FMRFamide-related peptides (FaRPs) on dispersed muscle
fibres from the marine turbellarian, Procerodes littoralis have been examined. Confocal scanning laser microscopy coupled
with fluorescein isothiocyanate (FITC) or tetramethylrhodamine (TRITC)-labelled phalloidin revealed a highly developed
body wall muscle system with circular, longitudinal and diagonal layers of muscle fibres. Dispersed muscle fibres
contracted when depolarized by exposure to extracellular media with elevated K+ (15â100 mM) in a
concentration-dependent manner, with a maximal response of 87% achieved at [ges ] 75 mM. 5-Hydroxytryptamine (5-HT) induced
concentration-dependent muscle contraction between 0·01 and 1000 ΌM, with 10 ΌM producing a near maximal contraction
response of 75%. Acetylcholine (ACh) had less pronounced excitatory effects (0·01â1000 ÎŒM), inducing contraction of
only 32% of the fibres at 100 ÎŒM. The flatworm FMRFamide-related peptides (FaRPs), GYIRFamide, YIRFamide and
GNFFRFamide each had concentration-dependent myocontractile effects, indicating the occurrence of at least 1 FaRP
receptor on P. littoralis muscle fibres. At 10 ÎŒM peptide, GNFFRFamide induced contractions in < 40% of the muscle
fibres examined, whereas YIRFamide and GYIRFamide induced contraction in 70 and 75%of muscle fibres, respectively.
The order of potency of the peptides was: GYIRFamide > YIRFamide > GNFFRFamide. Pre-incubation of the muscle
fibres in 5 ÎŒM 5-HT significantly reduced the responses to GYIRFamide, YIRFamide and 5-HT, while the responses to
high K+ remained unaltered. Muscle fibres pre-incubated in GYIRFamide (0·1 ΌM) were also less responsive to 5-HT but
not to ACh and high-K+. The GYIRFamide analogue, GYIRdFamide, did not induce muscle contraction (0·01â100 ÎŒM)
per se, but when co-applied with the myoactive peptides GYIRFamide, YIRFamide or GNFFRFamide, it significantly
blocked their ability to elicit contractions. This suggests that the peptides tested may act via a common muscle-based
neuropeptide receptor. GYIRdFamide did not alter the contractile effects of high K+, 5-HT or ACh. Collectively, these
results indicate that FaRPs, 5-HT and ACh all have the potential to cause muscle contraction in flatworms and that
5-HT and FaRPs alter muscle sensitivity to each other, but do not influence the ability of flatworm muscle fibres to
contract.</jats:p