The anatomy and physiology of the posterior stomach nerve (p.s.n.) in some decapod crustacea

1969 ◽  
Vol 171 (1025) ◽  
pp. 465-482 ◽  
Keyword(s):  
Sensory System ◽  
Posterior Part ◽  
Gastric Mill ◽  
Stomatogastric Nervous System ◽  
Anatomy And Physiology ◽  
Cancer Pagurus ◽  
Spontaneous Movements ◽  
Decapod Crustacea ◽  
Numerous Cell ◽  
Repetitive Electrical Stimulation

One of the major paired nerves in the decapod stomatogastric nervous system innervates the posterior part of the gastric mill. The morphology has been completely described previously only in Pugettia producta . This nerve is called the posterior stomach nerve (p.s.n.) in this paper. It is redescribed for Homarus vulgaris , and less detailed information is given for Palinurus vulgaris and Cancer pagurus . In these three species the p.s.n. contains numerous cell bodies. The majority of the cells are in one group and the long distal processes of these cells form a large proportion of the fibres in the nerve which runs to the gastric mill. Many of these fibres terminate by ramifying in the connective tissue which invests the ossicles of the gastric mill. The Brachyuran C. pagurus was used for most of the physiological experiments reported here. Only a small percentage of the animals exhibited spontaneous movements of the gastric mill when the carapace was removed and this activity ceased rapidly. However, a cycle of movements was usually observed in the active gastric mills and the p.s.n. contains many elements which respond to these normal movements. The p.s.n. does not appear to contain motor fibres. In tracellular recordings show that cells in the p.s.n. are proprioceptors. The distal processes of the major group of cells are morphologically dendrites, but they probably support action potentials. Repetitive electrical stimulation of a p.s.n. when it is isolated from the gastric mill evokes changes in the outut from the stomatogastric ganglion. The p.s.n. sensory system could therefore function in the normal reflex control of the activity of the gastric mill. This investigation may assist in the analysis of the functions of the stomato ­ gastric ganglion.

The neurophysiology of respiration in decapod crustacea. II. The sensory system

1969 ◽  
Vol 47 (3) ◽  
pp. 435-441 ◽  
Author(s):  
Valerie M. Pasztor
Keyword(s):  
Connective Tissue ◽  
Sensory Input ◽  
Respiratory Rhythm ◽  
Sensory System ◽  
Nerve Fibers ◽  
Rhythm Generator ◽  
Decapod Crustacea ◽  
New Type

The mechanoreceptors of the respiratory appendage were studied by histological and electrophysiological techniques.A new type of mechanoreceptor is described and named the "oval organ". It consists of a specialized oval patch of cuticle 1–2 mm in length which is traversed by a spine or longitudinal thickening. Closely applied to the cuticle is a pad of connective tissue richly supplied with dendrites from two large nerve fibers. The orientation of the spine and the dendrites ensures that the receptor responds preferentially to certain stresses or foldings of the oval organ. It lies at the base of the scaphognathite on the dorsal surface.No internal proprioceptors were observed. Movements of the appendage are signalled either by the oval organ, epidermal receptors, or hair sensilla.The possible effect of sensory input upon the central respiratory rhythm generator is discussed.

The Pharmacological Profile of the Acetylcholine Response of a Crustacean Muscle

1980 ◽  
Vol 88 (1) ◽  
pp. 147-160
Author(s):  
EVE MARDER ◽  
DANIÈLE PAUPARDIN-TRITSCH
Keyword(s):  
Acetylcholinesterase Activity ◽  
Gastric Mill ◽  
Muscarinic Agonists ◽  
Pharmacological Profile ◽  
Cancer Borealis ◽  
Cancer Irroratus ◽  
Pharmacological Analysis ◽  
Crustacean Muscle ◽  
Cancer Pagurus ◽  
High Concentrations

A pharmacological analysis was made of the depolarizing acetylcholine (ACh) response found on the gastric mill 1 muscles of the crabs Cancer pagurus, Cancer irroratus and Cancer borealis. Acetylcholine, carbamylcholine, trimethylammonium, nicotine, and dimethyl-4-phenyl-piperazinium were effective in producing contractures and depolarizations in these muscles. No response to decamethonium, suberyldicholine, acetyl-β-methylcholine, carbamyl-β-methylcholine, pilocarpine and oxotremorine could be detected. High concentrations of muscarinic agonists (10−4 to 10−3 M) potentiated and prolonged the ACh iontophoretic response. When the acetylcholinesterase activity was inhibited with neostigmine, or when the response was elicited with carbamylcholine, muscarinic agonists partially inhibited the response. ACh responses were most effectively blocked by vertebrate nicotinic ganglionic antagonists, including dihydro-β-erythroidine, pempidine, and mecamylamine. α-Bungarotoxin was without effect on the ACh response.

scholarly journals Similarities and differences in circuit responses to applied Gly1-SIFamide and peptidergic (Gly1-SIFamide) neuron stimulation

2019 ◽  
Vol 121 (3) ◽  
pp. 950-972 ◽  
Author(s):  
Dawn M. Blitz ◽  
Andrew E. Christie ◽  
Aaron P. Cook ◽  
Patsy S. Dickinson ◽  
Michael P. Nusbaum
Keyword(s):  
Activity Patterns ◽  
Projection Neuron ◽  
Projection Neurons ◽  
Gastric Mill ◽  
Stomatogastric Nervous System ◽  
Cancer Borealis ◽  
Axon Terminals ◽  
Motor Circuits ◽  
Commissural Neuron ◽  
Functional Context

Microcircuit modulation by peptides is well established, but the cellular/synaptic mechanisms whereby identified neurons with identified peptide transmitters modulate microcircuits remain unknown for most systems. Here, we describe the distribution of GYRKPPFNGSIFamide (Gly1-SIFamide) immunoreactivity (Gly1-SIFamide-IR) in the stomatogastric nervous system (STNS) of the crab Cancer borealis and the Gly1-SIFamide actions on the two feeding-related circuits in the stomatogastric ganglion (STG). Gly1-SIFamide-IR localized to somata in the paired commissural ganglia (CoGs), two axons in the nerves connecting each CoG with the STG, and the CoG and STG neuropil. We identified one Gly1-SIFamide-IR projection neuron innervating the STG as the previously identified modulatory commissural neuron 5 (MCN5). Brief (~10 s) MCN5 stimulation excites some pyloric circuit neurons. We now find that bath applying Gly1-SIFamide to the isolated STG also enhanced pyloric rhythm activity and activated an imperfectly coordinated gastric mill rhythm that included unusually prolonged bursts in two circuit neurons [inferior cardiac (IC), lateral posterior gastric (LPG)]. Furthermore, longer duration (>30 s) MCN5 stimulation activated a Gly1-SIFamide-like gastric mill rhythm, including prolonged IC and LPG bursting. The prolonged LPG bursting decreased the coincidence of its activity with neurons to which it is electrically coupled. We also identified local circuit feedback onto the MCN5 axon terminals, which may contribute to some distinctions between the responses to MCN5 stimulation and Gly1-SIFamide application. Thus, MCN5 adds to the few identified projection neurons that modulate a well-defined circuit at least partly via an identified neuropeptide transmitter and provides an opportunity to study peptide regulation of electrical coupled neurons in a functional context. NEW & NOTEWORTHY Limited insight exists regarding how identified peptidergic neurons modulate microcircuits. We show that the modulatory projection neuron modulatory commissural neuron 5 (MCN5) is peptidergic, containing Gly1-SIFamide. MCN5 and Gly1-SIFamide elicit similar output from two well-defined motor circuits. Their distinct actions may result partly from circuit feedback onto the MCN5 axon terminals. Their similar actions include eliciting divergent activity patterns in normally coactive, electrically coupled neurons, providing an opportunity to examine peptide modulation of electrically coupled neurons in a functional context.

scholarly journals Non-invasive MRI Studies of Ventilatory and Cardiovascular Performance in Edible Crabs Cancer pagurus During Warming Under Elevated CO2 Levels

2021 ◽  
Vol 11 ◽  
Author(s):  
Bastian Maus ◽  
Sebastian Gutsfeld ◽  
Christian Bock ◽  
Hans-Otto Pörtner
Keyword(s):  
Oxygen Uptake ◽  
Thermal Tolerance ◽  
Decapod Crustacean ◽  
Temperature Dependent ◽  
Non Invasive ◽  
Cancer Pagurus ◽  
Decapod Crustacea ◽  
Infra Red ◽  
Cardiovascular Performance ◽  
Flow Through

The thermal tolerance of marine decapod crustacea is defined through their capacities for oxygen uptake and distribution. High ambient CO2 levels were previously shown to reduce hemolymph oxygen levels at enhanced cardiac performance during warming. This study investigated the impacts of warming under two CO2 levels on ventilation and hemolymph circulation in edible crabs Cancer pagurus. It also highlights changes in the ventilatory and cardiac pauses displayed by Decapoda under routine metabolism. Animals were exposed to step-wise, sub-critical warming (12–20°C over 5 days) under control (470 μatm) and high (1,350 μatm) water PCO2. Flow-through respirometry was combined with magnetic resonance imaging and infra-red photoplethysmography to allow for simultaneous, non-invasive measurements of metabolic rates (M˙O2), ventilation and cardiovascular performance. Crabs spent significantly more time in a low M˙O2 state (metabolic pause), when experiencing high CO2 conditions above 16°C, compared to normocapnic warming. Heart rates leveled off beyond 18°C at any CO2 level. Cardiac output continued to increase with high-CO2-warming, due to elevated cardiac stroke volumes. Consequently, temperature-dependent branchial hemolymph flow remained unaffected by CO2. Instead, a suppressing effect of CO2 on ventilation was found beyond 16°C. These results indicate constrained oxygen uptake at stable cardiovascular performance in a decapod crustacean.Cancer pagurus: urn:lsid:zoobank.org:act:B750F89A-84B5-448B-8D80-EBD724A1C9D4

scholarly journals On the nature and permeability of chitin. I.--The chitin lining the foregut of decapod crustacea and the function of the tegumental glands

1932 ◽  
Vol 111 (772) ◽  
pp. 298-329 ◽  
Keyword(s):  
External Medium ◽  
Specific Rotation ◽  
The Body ◽  
Animal Kingdom ◽  
Entire Surface ◽  
Large Size ◽  
Research Material ◽  
Cancer Pagurus ◽  
Decapod Crustacea ◽  
Average Size

Chitin is widely distributed throughout the animal kingdom and also occurs in the Fungi. Wester (1910) has shown that it is present in all Arthropods, invariably in the exoskeleton and lining the respiratory systems and except in some Arachnids, in the greater part of the gut. In the Mollusca it occurs in the jaws and radulæ, in the shell and sometimes in the gut of Cephalopods and sometimes in the shell and lining of siphons in Lamellibranchs. The setæ of Annelids are of chitin and occasionally, as in Lumbricus and Aphrodile , the gut is lined with it. Chitin is also present in the shell, peduncle and spines of some Brachiopods, e. g., Lingula, in some Plyzoa, in the Hydroids and very occasionally, as in the gemmules of Spongilla, in the porifera. According to Wester, it never occurs in protoza, Echinodrema, worms other than Annelids or in vertebrates. Wherever it occur, chitin gives the same chemical reactions (Zander, 1897 ; Wester, 1910) and has the same physical properties, e. g., specific gravity and refractive index (Sollas, 1907 ; Becking and Chamberlin, 1925) and specific rotation which is always lævorotatory (Irvine, 1909). It is surprising that so little is known about the properties of this very important substance. In the Arthropods especially, where it covers the entire surface of the body and where respiration and in some cases absorption in the gut-indeed practically all interchange between the interior of the body and the external medium-must take place through it, exact knowledge of the permeability of chitin and of the condition which control this is clearly essential for a full understanding of the life of the animal. It was the almost complete absence of knowledge on this subject which led to the initiation of this series of researches. Ideal material for this purpose was found in the uncalcified chitin which lines the foregut (“œesphagus” and “stomach”) of the Decapod Crustacea, of which relatively large pieces can be obtained from animals of average size. The lobster, Homarus vulgaris , owing to the relatively large size of the foregut, provided the great bulk of the research material, other large Decapods, such a Palinurus vulgaris , Cancer pagurus, Maia squinado and Carcinus mœnas , being used for comparative purposes.

Hormonal Modulation of Two Coordinated Rhythmic Motor Patterns

2010 ◽  
Vol 104 (2) ◽  
pp. 654-664
Author(s):  
Debra E. Wood ◽  
Melissa Varrecchia ◽  
Michael Papernov ◽  
Denise Cook ◽  
Devon C. Crawford
Keyword(s):  
Motor Pattern ◽  
Projection Neuron ◽  
Frequency Regulation ◽  
Gastric Mill ◽  
Stomatogastric Nervous System ◽  
Motor Patterns ◽  
Rhythmic Motor ◽  
Hormonal Modulation ◽  
Frequency Relationship ◽  
Pyloric Rhythm

Neuromodulation is well known to provide plasticity in pattern generating circuits, but few details are available concerning modulation of motor pattern coordination. We are using the crustacean stomatogastric nervous system to examine how co-expressed rhythms are modulated to regulate frequency and maintain coordination. The system produces two related motor patterns, the gastric mill rhythm that regulates protraction and retraction of the teeth and the pyloric rhythm that filters food. These rhythms have different frequencies and are controlled by distinct mechanisms, but each circuit influences the rhythm frequency of the other via identified synaptic pathways. A projection neuron, MCN1, activates distinct versions of the rhythms, and we show that hormonal dopamine concentrations modulate the MCN1 elicited rhythm frequencies. Gastric mill circuit interactions with the pyloric circuit lead to changes in pyloric rhythm frequency that depend on gastric mill rhythm phase. Dopamine increases pyloric frequency during the gastric mill rhythm retraction phase. Higher gastric mill rhythm frequencies are associated with higher pyloric rhythm frequencies during retraction. However, dopamine slows the gastric mill rhythm frequency despite the increase in pyloric frequency. Dopamine reduces pyloric circuit influences on the gastric mill rhythm and upregulates activity in a gastric mill neuron, DG. Strengthened DG activity slows the gastric mill rhythm frequency and effectively reduces pyloric circuit influences, thus changing the frequency relationship between the rhythms. Overall dopamine shifts dependence of frequency regulation from intercircuit interactions to increased reliance on intracircuit mechanisms.

Feeding State-Dependent Modulation of Feeding-Related Motor Patterns

2021 ◽  
Author(s):  
Aaron P. Cook ◽  
Michael P. Nusbaum
Keyword(s):  
Neural Circuit ◽  
Projection Neuron ◽  
Neuron Activity ◽  
Gastric Mill ◽  
Stomatogastric Nervous System ◽  
Cancer Borealis ◽  
Motor Patterns ◽  
State Dependent ◽  
Reduced Activity ◽  
Time Point

Studies elucidating modulation of microcircuit activity in isolated nervous systems have revealed numerous insights regarding neural circuit flexibility, but this approach limits the link between experimental results and behavioral context. To bridge this gap, we studied feeding behavior-linked modulation of microcircuit activity in the isolated stomatogastric nervous system (STNS) of male Cancer borealis crabs. Specifically, we removed hemolymph from a crab that was unfed for ≥24 h ('unfed' hemolymph) or fed 15 min - 2 h before hemolymph removal ('fed' hemolymph). After feeding, the first significant foregut emptying occurred >1 h later and complete emptying required ≥6 h. We applied the unfed or fed hemolymph to the stomatogastric ganglion (STG) in an isolated STNS preparation from a separate, unfed crab to determine its influence on the VCN (ventral cardiac neuron)-triggered gastric mill (chewing)- and pyloric (filtering of chewed food) rhythms. Unfed hemolymph had little influence on these rhythms, but fed hemolymph from each examined time-point (15 min, 1- or 2 h post-feeding) slowed one or both rhythms without weakening circuit neuron activity. There were also distinct parameter changes associated with each time-point. One change unique to the 1 h time-point (i.e. reduced activity of one circuit neuron during the transition from the gastric mill retraction to protraction phase) suggested the fed hemolymph also enhanced the influence of a projection neuron which innervates the STG from a ganglion isolated from the applied hemolymph. Hemolymph thus provides a feeding state-dependent modulation of the two feeding-related motor patterns in the C. borealis STG.

Dual modulatory effects on feedback from a proprioceptor in the crustacean stomatogastric nervous system

2021 ◽  
Author(s):  
Davis Grininger ◽  
John T. Birmingham
Keyword(s):  
Nervous System ◽  
Inhibitory Action ◽  
Muscle Contractions ◽  
Proprioceptive Feedback ◽  
Gastric Mill ◽  
Stomatogastric Nervous System ◽  
Cancer Borealis ◽  
Muscle Stretch ◽  
Excitatory Action ◽  
Central Network

Neuromodulatory actions that change the properties of proprioceptors or the muscle movements to which they respond necessarily affect the feedback provided to the central network. Here we further characterize the responses of the gastropyloric receptor 1 (GPR1) and gastropyloric receptor 2 (GPR2) neurons in the stomatogastric nervous system of the crab Cancer borealis to movements and contractions of muscles, and we report how neuromodulation modifies those responses. We observed that the GPR1 response to contractions of the gastric mill 4 (gm4) muscle was absent, or nearly so, when the neuron was quiescent but robust when it was spontaneously active. We also found that the effects of four neuromodulatory substances (GABA, serotonin, proctolin and TNRNFLRFamide) on the GPR1 response to muscle stretch were similar to those previously reported for GPR2. Finally, we showed that an excitatory action on gm4 due to proctolin combined with an inhibitory action on GPR2 due to GABA can allow for larger muscle contractions without increased proprioceptive feedback.

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