Nervous control of male sexual drive in the hermaphroditic snail

1997 ◽  
Vol 200 (5) ◽  
pp. 941-951 ◽  
Author(s):  
P Boer ◽  
R Jansen ◽  
J Koene ◽  
A Maat
Keyword(s):  
Social Isolation ◽  
Firing Pattern ◽  
Lymnaea Stagnalis ◽  
Prostate Gland ◽  
Pond Snail ◽  
Nervous Control ◽  
Sexual Drive ◽  
Motivational Model ◽  
Behavioural Experiments

We studied the role of the prostate gland in determining the level of male sexual drive in the hermaphroditic pond snail Lymnaea stagnalis. Male sexual drive is high after a period of social isolation and decreases after copulation as a male. A positive correlation exists between the level of male sexual drive and the volume of the prostate gland. Like male sexual drive, the volume of the prostate gland increases during a period of social isolation and decreases after copulation as a male. Behavioural experiments demonstrated that animals with a lesion of the nerve that innervates the prostate gland (NP1) have a lower level of male sexual drive after social isolation than control animals. However, lesion of NP1 did not affect the increase in the volume of the prostate gland caused by social isolation. Extracellular recordings from NP1 in a semi-intact preparation show a change in firing pattern during an experimentally induced increase in prostate gland volume. The results indicate that NP1 serves as a nervous pathway for the male sexual drive. We propose a simple motivational model for male sexual behaviour in L. stagnalis in which the volume of the prostate gland sets the level of male sexual drive.

Schistosomicidal activities ofLymnaea stagnalishaemocytes: the role of oxygen radicals

Parasitology ◽  
1994 ◽  
Vol 109 (4) ◽  
pp. 479-485 ◽  
Author(s):  
C. M. Adema ◽  
E. C. Van Deutekom-Mulder ◽  
W. P. W. Van Der Knaap ◽  
T. Sminia
Keyword(s):  
Nadph Oxidase ◽  
Protocatechuic Acid ◽  
Lymnaea Stagnalis ◽  
Pond Snail ◽  
Oxygen Intermediates ◽  
Mediate Cytotoxicity ◽  
Specific Antagonist ◽  
Trichobilharzia Ocellata

SUMMARYMacrophage-like defence cells (haemocytes) of the pond snailLymnaea stagnalismediate cytotoxicity through reactive oxygen intermediates (ROIs). This activity is NADPH-oxidase dependent, as in mammalian phagocytes during the respiratory burst. In this study, mother sporocysts of schistosomes, the compatibleTrichobilharzia ocellataand the incompatibleSchistosoma mansonievokein vitroROI activities (detected by luminol dependent chemiluminescence, LDCL) fromL. stagnalishaemocytes.S. mansoniis encapsulated by haemocytes and eliminated, whereasT. ocellataescapes encapsulation and survives. Both schistosomes were equally susceptible toin vitrooxidative damage from exposure to hydrogen peroxide and to ROIs generated by a xanthine/xanthine oxidase system. Protocatechuic acid, a specific antagonist of NADPH-oxidase, delayed the killing ofT. ocellataandS. mansonisporocysts by haemocytes of resistant snails (Biomphalaria glabrata and L. stagnalis, respectively). We conclude that ROIs take part in haemocyte-mediated cytotoxicity. However, neither a snail's capability to generate ROIs, nor a schistosome's susceptibility to ROIs, determine snail/schistosome incompatibility. Snail/schistosome compatibility is rather determined by the parasite's ability modulate haemocyte behaviour such that effective encapsulation and the generation of lethal concentrations of ROIs are prevented.

Central Coordination of Buccal and Pedal Neuronal Activity in the Pond Snail Lymnaea Stagnalis

1988 ◽  
Vol 136 (1) ◽  
pp. 103-123
Author(s):  
M. A. KYRIAKIDES ◽  
C. R. MCCROHAN
Keyword(s):  
Central Pattern Generator ◽  
Body Wall ◽  
Lymnaea Stagnalis ◽  
Pattern Generator ◽  
Pond Snail ◽  
Buccal Ganglion ◽  
Buccal Ganglia ◽  
Feeding Cycle ◽  
Central Coordination

Cyclical synaptic inputs were recorded from identified giant neurones and neuronal cluster cells in the pedal ganglia of Lymnaea stagnalis. They occurred in phase with rhythmical inputs to buccal ganglion motoneurones, which have been shown to originate from interneurones of the buccal central pattern generator for feeding. In pedal neurones, the cyclical inputs were mainly inhibitory, and occurred predominantly during the radula retraction phase of the feeding cycle. Tonic depolarization of higher-order interneurones in the feeding system, to activate the buccal central pattern generator, led to the onset of cyclical inputs to pedal neurones. These inputs were abolished after cutting the cerebrobuccal connectives, supporting the hypothesis that they originate from the buccal ganglia. The possible role of these inputs in coordinating foot and body wall movements with the buccal feeding rhythm is discussed.

THE NEURAL CONTROL OF EGG-LAYING BEHAVIOUR IN THE POND SNAIL LYMNAEA STAGNALIS: MOTOR CONTROL OF SHELL TURNING

1994 ◽  
Vol 197 (1) ◽  
pp. 79-99
Author(s):  
P Hermann ◽  
A Maat ◽  
R Jansen
Keyword(s):  
Neural Control ◽  
Lymnaea Stagnalis ◽  
Longitudinal Muscle ◽  
Egg Laying ◽  
Neuroendocrine Cells ◽  
Pond Snail ◽  
Motor Neurones ◽  
Turning Behaviour ◽  
Behavioural Experiments ◽  
The Right

Behavioural and neurophysiological techniques were used to study the neuronal control of shell turning during egg-laying in the pond snail Lymnaea stagnalis. Egg-laying consists of three phases: resting, turning and oviposition, and is triggered by an electrical discharge in a group of neuroendocrine cells, the caudodorsal cells. During the discharge, several peptides encoded on two CDCH genes are known to be released. Behavioural experiments in which different combinations of nerves were lesioned indicated that the inferior cervical nerves are necessary for turning behaviour to occur. The right inferior cervical nerve innervates the right dorsal longitudinal muscle and contains axons of neurones that are active just prior to, and during, shell movements in freely behaving animals. These axons are probably the axons of motor neurones. The motor neurones of the dorsal longitudinal muscle were identified in the cerebral A and pedal N clusters. We have demonstrated that there is a correlation between the state of excitability of the caudodorsal cells and the electrical activity of the pedal N motor neurones. Our results indicate that the pedal N motor neurones are involved in executing the turning phase during egg-laying.

scholarly journals Identification, presence, and possible multifunctional regulatory role of invertebrate gonadotropin-releasing hormone/corazonin molecule in the great pond snail (Lymnaea stagnalis)

2020 ◽  
Author(s):  
István Fodor ◽  
Zita Zrinyi ◽  
Péter Urbán ◽  
Róbert Herczeg ◽  
Gergely Büki ◽  
...  
Keyword(s):  
Lymnaea Stagnalis ◽  
Biological Effects ◽  
Gonadotropin Releasing Hormone ◽  
Pond Snail ◽  
Releasing Hormone ◽  
Main Driver ◽  
The Central Nervous System ◽  
Global Understanding ◽  
Species Specific

AbstractIn the last years, the interpretation of gonadotropin-releasing hormone (GnRH) neuropeptide superfamily has changed tremendously. One main driver is the investigation of functions and evolutionary lineage of previously identified molluscan GnRH molecules. Emerging evidence suggests not only reproductive, but also diverse biological effects of these molecules and proposes they should most likely be called corazonin (CRZ). Clearly, a more global understanding necessitates further exploration of species-specific functions and structure of invGnRH/CRZ peptides. Towards this goal, we have identified the full-length cDNA of invGnRH/CRZ peptide in an invertebrate model species, the great pond snail Lymnaea stagnalis, termed ly-GnRH/CRZ, and characterized the transcript and peptide distribution in the central nervous system (CNS) and peripheral organs. Our results are consistent with previous data that molluscan GnRHs are more related to CRZs and serve diverse functions. For this, our findings support the notion that peptides originally termed molluscan GnRH are multifunctional modulators and that nomenclature change should be taken into consideration.

Role of Neuropeptides Encoded on CDCH-1 Gene in the Organization of Egg-Laying Behavior in the Pond Snail, Lymnaea stagnalis

1997 ◽  
Vol 78 (6) ◽  
pp. 2859-2869 ◽  
Author(s):  
Petra M. Hermann ◽  
Robert P. J. de Lange ◽  
Anton W. Pieneman ◽  
Andries ter Maat ◽  
Rene F. Jansen
Keyword(s):  
Gene Family ◽  
Motor Neurons ◽  
Lymnaea Stagnalis ◽  
Egg Laying ◽  
Pond Snail ◽  
Excitatory Effect ◽  
Turning Behavior ◽  
Fiber Tracts ◽  
The Individual

Hermann, Petra M., Robert P. J. de Lange, Anton W. Pieneman, Andries ter Maat, and Rene F. Jansen. Role of neuropeptides encoded on CDCH-1 gene in the organization of egg-laying behavior in the pond snail, Lymnaea stagnalis. J. Neurophysiol. 78: 2859–2869, 1997. Egg laying in the pond snail Lymnaea stagnalis is triggered by a discharge of the neuroendocrine caudodorsal cells (CDCs). The CDCs expresses three different caudorsal cell hormone (CDCH) genes. This gene family expresses, in total, 11 different peptides among which is the ovulation hormone. Besides the CDCs, the CDCH gene family is expressed in other central and peripheral neurons. In this study, we investigated the roles the different CDCH peptides play in the organization of egg-laying behavior. Egg-laying behavior is a sequence of stereotyped movements in which three phases can be distinguished: resting, turning, and oviposition. We have used the excitation of right pedal N (RPeN) motor neurons as a simple analogue of shell-turning behavior, one of the elements of egg-laying behavior. RPeN motor neurons were inhibited during the resting phase of egg laying but were subsequently excited at the onset of and during the turning phase. The excitatory effect could be evoked by application of beta3-CDCP on RPeN motor neurons in the CNS as well as in isolation but not by the ovulation hormone, alpha-CDCP or Calfluxin, the other CDCH-1 peptides tested. The ovulation hormone itself caused inhibition of RPeN motor neurons. Anti-CDCH–1 positive fiber tracts were found close to the cell bodies and axons of the RPeN motor neurons. Electrical stimulation of a nerve that contains these fibers resulted in excitation of the RPeN motor neurons. The effects of injection of CDCH-1 peptides into intact animals correlated well with the effects of these peptides on RPeN motor neurons. Injection of beta3-CDCP or alpha-CDCP into intact animals resulted in immediate turning behavior in the absence of egg laying itself. The ovulation hormone and Calfluxin had no immediate effect on the behavior. Furthermore, our data indicate that the individual CDCH-1 peptides act on different targets.

Motives for Social Isolation Following a Negative Emotional Episode

2018 ◽  
Vol 77 (3) ◽  
pp. 127-131
Author(s):  
Gérald Delelis ◽  
Véronique Christophe
Keyword(s):  
Social Isolation ◽  
Social Affiliation ◽  
Semantic Categorization ◽  
Future Studies ◽  
Cognitive Regulation ◽  
Emotional Event ◽  
Regulation Strategies ◽  
Emotional Events

Abstract. After experiencing an emotional event, people either seek out others’ presence (social affiliation) or avoid others’ presence (social isolation). The determinants and effects of social affiliation are now well-known, but social psychologists have not yet thoroughly studied social isolation. This study aims to ascertain which motives and corresponding regulation strategies participants report for social isolation following negative emotional events. A group of 96 participants retrieved from memory an actual negative event that led them to temporarily socially isolate themselves and freely listed up to 10 motives for social isolation. Through semantic categorization of the 423 motives reported by the participants, we found that “cognitive clarification” and “keeping one’s distance” – that is, the need for cognitive regulation and the refusal of socioaffective regulation, respectively – were the most commonly and quickly reported motives for social isolation. We discuss the findings in terms of ideas for future studies aimed at clarifying the role of social isolation in health situations.

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