Central Nervous System Of Invertebrates Research Articles

Phylogenetic study of the arginine-vasotocin/arginine-vasopressin-like immunoreactive system in invertebrates

1. 1. A phylogenetic study of arg-vasotocin (AVT)/arg-vasopressin (AVP)-like immunoreactive cells was performed by the PAP method in the central nervous system of invertebrates. 2. 2. The immunoreactivity was detected in the nerve cells of Hydra magnipapillata of the Coelenterata: Neanthes japonica and Pheretima communissima of the Annelida; Pomacea canaliculata, Aplysia kurodai, Oncidium verrucosum, Bradybaena similaris, Achatina fulica, Limax marginatus and Meretrix lamarckii of the Mollusca; Gnorimosphaeroma rayi, Hemigrapsus sanguineus, Gryllus bimaculatus and Baratha brassicae of the Arthropoda; Asterina pectinifera of the Echinodermata; and Halocynthia roretzi of the Protochordata. 3. 3. No immunoreactivity was detected in Bipalium sp. of the Platyhelminths, or in Procambarus clarkii and Helice tridens of the Arthropoda. 4. 4. From these results, it appears that AVT/AVP is a phylogenetically ancient peptide which is present in a wide variety of invertebrates. 5. 5. The actions of AVT/AVP and its presence in invertebrates are discussed.

Phylogenetic study of the oxytocin-like immunoreactive system in invertebrates

1. 1. A phylogenetic study of oxytocin (OXT)-like immunoreactive cells was performed by the PAP method in the central nervous system of invertebrates. 2. 2. The immunoreactivity was detected in the nerve cells of Hydra magnipapillata of the Coelenterata; Neanthes japonica and Pheretima communissima of the Annelida; Oncidium verrucosum, Limax marginatus and Meretrix lamarckii of the Mollusca; and Baratha brassica of the Arthropoda. 3. 3. No immunoreactive cells were found in Bipalium sp. of the Platyhelminthes; Pomacea canaliculata, Aplysia kurodai, Bradybaena similaris and Achatina fulica of the Mollusca; and Gnorimosphaeroma rayi, Procambarus clarkii, Hemigrapsus sanguineus, Helice tridens and Gryllus bimaculatus of the Arthropoda; Asterina pectinifera of the Echinodermata; and Halocynthia roretzi of the Protochordata. 4. 4. These results demonstrate that an OXT-immunoreactive substance is widely present not only in vertebrates but also in invertebrates. 5. 5. OXT seems to have been introduced into these invertebrates at an early stage of their phylogenetic history.

Competition controls the growth of an identified axonal arborization.

The shape of the axonal arborization was studied in an identified insect sensory neuron. The distribution of presynaptic varicosities within an axonal arbor was shown to be modulated by the density of neighboring terminals. Removal of neighbors near one portion of the axon terminal increased the growth rate in the denervated region and caused a compensatory retraction in other regions. The results support the hypothesis that the size of an axonal arbor is determined intrinsically, whereas the distribution of varicosities within the terminal is determined extrinsically by neighboring terminals. These findings provide a direct demonstration of the effects of competition on an identified nerve cell, as well as one of the first examples of competitive interactions in an invertebrate central nervous system.

Use of focused ultrasound for stimulation of nerve structures

Pulsed focused ultrasound can stimulate the receptor and conductive nerve structures of humans and animals as well as the neurons of the central nervous system of invertebrates. The possibility of a wide practical use of this method in medicine and physiology is considered. For example, the stimulating ability of focused ultrasound is applied to the diagnosis of neurological diseases, to the study of skin and tissue sensitivity in man, to the diagnosis of hearing disorders, and to the introduction of auditory information to the deaf with certain forms of hearing pathology. The factors that affect focused ultrasound as a stimulus for the irritation of nerve structures are discussed.

Histochemical localization of FMRFamide-like immunoreactivity in the rat brain

Molluscan cardioexcitatory neuropeptide or FMRFamide is present in the invertebrate central nervous system (CNS) and FMRFamide like peptide has been demonstrated in the mammalian CNS. In this study, the distribution of FMRFamide immunoreactivity was studied in rat brain using the indirect immunofluorescent method. The highest number of FMRFamide staining cell bodies was found in the nucleus (n) arcuatus. N. paraventricularis, n. hypothalamus, n. ventromedialis, n. dorsomedialis and n. tractus solitarii also contained high numbers. FMRFamide positive nerve fibers and terminals were widely distributed. The septal complex contained high densities, especially in n. interstitialis striae terminalis. N. paraventricularis hypothalami, n. paraventricularis, n. hypothalamicus, n. ventromedialis and n. dorsomedialis showed a high to very high degree of immunoreactivity. In myelencephalon, n. tractus solitarii had the densest innervation. Spinal cord had a dense band of FMRFamide positive fibers in lamina I and II of the dorsal horn. The present findings support a neurotransmitter role for a FMRFamide like peptide in the mammalian brain, possibly related to endocrine and autonomic regulation as well as pain modulation.

Current source-density analysis in the mushroom bodies of the honeybee (Apis mellifera carnica)

Information processing in the mushroom bodies which are an important part of most invertebrate central nervous systems was analysed by extracellular electrophysiological techniques. The mushroom bodies consist of layers of parallel intrinsic neurons which make synaptic contact with extrinsic input and output neurons. The intrinsic neurons (approximately 170,000/mushroom body) have very small axon diameters (0.1–1 μm) which makes it difficult to record their activity intracellularly. In order to analyse the functional properties of this neuropil field potentials were measured extracellularly. Series of averaged evoked potentials (AEPs) were recorded along electrode tracks at consecutive depth intervals in different parts of the mushroom bodies of the bee. These potentials were elicited by olfactory, mechanical and visual stimuli. In order to locate the synaptic areas generating these potentials, current source-densities (CSD) were calculated using the consecutively measured evoked potentials. The conductivities of the extracellular space along the electrode tracks in the pedunculus and calyx and in part of the alpha-lobe of the mushroom bodies were found to be constant. The CSD analysis reveals a complex pattern of source-sink distributions in the mushroom bodies. There is a high degree of correlation between current sinks and sources detected by CSD analysis and the morphological distribution of neurons. The CSD analysis shows that the inputs and outputs of the mushroom bodies involve multimodal synaptic interactions, whereas information processing in the intrinsic Kenyon-cells is limited to sensory inputs from the antenna. Comparison of the electrophysiological with the histological results shows that the intrinsic cells of the mushroom bodies are physiologically not a homogeneous group as is often proposed. Among the intrinsic neurons clearly defined areas of current sources and sinks can be identified and attributed to Kenyon-cells in different layers.

Do neuronal signals regulate potassium flow in glial cells? Evidence from an invertebrate central nervous system.

Experiments were conducted with the aid of intracellular microelectrodes to study physiological properties of neuropile glial cells in the central nervous system of the medicinal leech. The results showed significant contributions of both K+ and Cl- ions to the membrane potential. The transmitter substance 5-hydroxytryptamine increased the K+ conductance of the cell membrane. On the basis of these experiments, a model for potassium homeostasis in leech neuropile is suggested, according to which excess K+ ions in the extracellular space lead to passive KCl fluxes across the glial cell membrane and the transmitter 5-hydroxytryptamine induces a K+ release from glial cells into the extracellular space. Since 5-hydroxytryptamine is known to be an inhibitory transmitter in the leech central nervous system, this release will occur in regions with inactive neurons, which may be specially well suited for neuronal reaccumulation of K+ ions.

Stereoisomeric identity of octopamine in the central nervous system of invertebrates

A method for the analysis of octopamine enantiomers has been developed based on the high-performance liquid chromatographic separation of diastereoisomers obtained by derivatization with the pentafluorophenyl ester of tert- butyloxycarbonyl- l-leucine . The sensitivity of the method can be extended greatly for use in studies of small biological samples by preparing the Boc- l-leucyl derivative of radiolabelled octopamine isolated from tissues treated with labelled octopamine precursors followed by analysis of chromatographic fractions for radioactivity. Using this method it was shown that octopamine synthesized from radiolabelled l-tyrosine by incubated brains of the bertha armyworm, Mamestra configurata, had the d-configuration. The same result was obtained with octopamine synthesized from radiolabelled tyramine by the action of tyramine β-hydroxylase in homogenates of brains of M. configurata, the lady beetle, Hippodamia convergens, the snail, Helosoma sp. and the crayfish, Orconecties sp. These results demonstrate that it is d-octopamine which is present in the central nervous system of invertebrates and complement a recent report ( Goosey and Candy, 1980) that d-octopamine occurs in the haemolymph of an insect.

Localization of[3H]-2-deoxyglucose in single molluscan neurones.

The glucose analogue 2-deoxyglucose (2-DG) can be used quantitatively to measure metabolic activity and is widely used qualitatively for mapping functional activity in the brain. The resolution (meaning the full width at half maximum of the grain density distribution around a line source) of the technique using [14C]-2-DG and X-ray film is limited to about 100 micrometers. Attempts have been made to improve the resolution using [3H]-2-DG (ref. 6) and cellular resolution has been achieved in the goldfish retina and with cultured mouse neurones. An anatomical technique for mapping the metabolic activity of individual neurones would be useful for studying invertebrate central nervous systems, which are relatively simple and stereotyped compared to vertebrate brains. The [3H]-2-DG technique was applied to an invertebrate in a study of the Drosophila visual system, though without cellular resolution. We present here modifications of the [3H]-2-DG technique to demonstrate localization of 2-DG in single neurones of Limax maximus, a gastropod mollusc, with a resolution of less than 1 micrometer.

General anaesthetic action in the invertebrate central nervous system

General anaesthetic action in the invertebrate central nervous system

Optical recording of neuronal activity in an invertebrate central nervous system: simultaneous monitoring of several neurons

1. Using an optical method for measuring membrane potential, we have been able to monitor action-potential activity simultaneously in 14 neurons of the supraesophageal ganglion of the barnacle. 2. Under favorable conditions, 4-mV synaptic potentials could also be detected optically.

Cholinergic synaptic transmission in invertebrate central nervous systems [proceedings

Piggott, S. M., Kerkut, G. E. & Walker, R. J. (1975) Comp. Biochem. Physiol. C 51,91-100 Rees, D. & Usherwood, P. N. R. (1972) Comp. Biochem. Physiol. A 43, 83-101 Ross, D. M. (1966) Symp. Zool. SOC. London, 16, Shank, R. P. & Freeman, A. R. (1975) J. Neurobiol. 6, 289-303 Shinozaki, H. & Shilbuya, I. (1976) Neurupharmacology 15, 145-147 Steiner, G. (1957) Naturwissenschuften 44, 70-71 Takeuchi, A. & Onodera, K. (1975) Neuropharrnacology 14,619-625 Usherwood, P. N. R. (1976) in Chemical Transmission in the Mammalian Central Nervous System (Hockrnan, C. H. & Berger, D., eds.), pp. 83-158, University Park Press, Baltimore, London and Tokyo Usherwood, P. N. R. & Cull-Candy, S. G. (1975) in Insect Muscle (Usherwood, P. N. R., ed.), chapter 4, Academic Press, New York and London Walther, C. & Usherwood, P. N. R. (1972) Verh. Drsch. Zod. Ges. 65, 309-312 Wander, H. R. & Hilgard, H. R. (1975) Comp. Biochem. Physiol. 50, 67-70 Wheal, H. V. & Kerkut, G. A. (1976) Comp. Pharmacol. 1, 51-55 Yarowsky, P. J. & Carpenter, D. 0. (1976) Nature (London) 192, 807-809 New York and London

Fine Structure of the Neuron Perinuclear Ring of Boophilus microplus1

The use of pyronine-malachite green (PMaG) for staining the RNA in invertebrate central nervous systems (Baker and Williams 1965) made it possible to use the perinuclear RNA ring as a marker in identifying the individual central nerve cell body with respect to its peripheral axon cut (Cohen and Jacklet 1965, Chow et al. 1973). Although many attempts were made to see the ultrastructural features that correspond to this RNA ring in insects observed histochemically with the light microscope (Young et al. 1970, Byers 1970), no data were reported in ticks. By using the tropical cattle tick, Boophilus microplus (Canestrini), as experimental material, I find that the RNA ring around the nucleus of the motor neurons in the tick synganglion consists of multiple profiles of rough endoplasmic reticulum and mitochondria intermingled between them.

A rapid method for the demonstration of nerve cell bodies in invertebrate central nervous systems

A rapid method for the demonstration of nerve cell bodies in invertebrate central nervous systems

Optical recording of impulses in individual neurones of an invertebrate central nervous system.

FOR many purposes it would be a great advantage if one could measure the activity of individual neurones without the use of an electrode. Since the discovery of changes in the optical properties of axons that occur during the action potential1,2, it has been possible, in principle, to accomplish this using optical techniques. Recently, this was achieved in a giant axon using a merocyanine dye; in a stained axon a single action potential gave rise to a fluorescence increase which was detectable with a signal-to-noise ratio greater than 10 : 1 (ref. 3). Because the membrane area observed in the giant axon experiments was about 103 times larger than that of a 50 µm cell body, it was by no means evident that this fluorescent probe would be sensitive enough to monitor electrical activity in smaller cells. Happily, it is; with the merocyanine dye, we are able to detect action potentials in individual sensory neurones of leech segmental ganglia. We hope that this technique can be developed into a powerful tool for studying the functional organisation of populations of neurones.

Chemical transmission in invertebrate central nervous systems and neuromuscular junctions.

Chemical transmission in invertebrate central nervous systems and neuromuscular junctions.

Changes in the Properties of Acetylcholinesterase in the Invertebrate Central Nervous System

Publisher Summary This chapter discusses the changes in the properties of Acetylcholinesterase in the invertebrate central nervous systems. In an insect such as the cockroach, there are two main chemical transmitters in the CNS. Acetylcholine (ACh) is the main excitatory transmitter and excites over 95 % of all the cells tested and γ-aminobutyric acid (GABA) is the main inhibitory transmitter and inhibits over 95 % of all the cells tested. The insect CNS is pharmacologically simpler than that of the vertebrates or the molluscs. This chapter studies changes in the chemistry of the insect nervous system following behavioral changes. It uses the preparation devised by Horridge, where he sets up two cockroaches where one received a shock every time its leg touched the saline, and the second cockroach) was yoked to the first so that it received a shock every time the first cockroach received a shock, regardless of the position of the leg. The first cockroach learned to keep its leg out of the saline whereas the second animal, even though it got the same number of shocks as the first, did not learn to keep its leg out of the saline.

Extracellular recording from single neurones in the olfactory centre of the cockroach.

VERY few reports have been published concerning the olfactory responses from single units in the central nervous system of invertebrates. This communication is concerned with the successful extracellular recording of single unit responses evoked by olfactory stimulation. It is emphasized that the response to odours can be classified into three categories: namely, “on” response; “on–off” response; and “off” response.

OXIDATION OF REDUCED NICOTINAMIDE NUCLEOTIDES IN THE CENTRAL NERVOUS SYSTEM OF SOME MARINE INVERTEBRATES.

INVESTIGATIONS carried out chiefly with mammalian brain have revealed the presence of several enzymatic systems catalysing the oxidation of reduced nicotinamide nucleotides the properties of which are briefly outlined as follows: (1) a mitochondrial system which catalyses the oxidation of NADH but not NADPH by oxygen the activity of which is inhibited by antimycin A and amytal1 (NADH and NADPH stand respectively for the reduced forms of nicotinamide adenine dinucleotide and nicotinamide adenine dinucleotide phosphate); (2) two microsomal systems which catalyse respectively the oxidation of NADH and NADPH by cytochrome c and are not inhibited by these drugs1; (3) two NAD(P)H dehydrogenases capable of acting on both nicotinamide nucleotides when certain quinones are added and which are strongly inhibited by low concentrations of dicumarol2–4; (4) an NADH–ferricyanide reductase relatively insensitive to dicumarol5; (5) an NADPH–glutathione reductase6. The mitochondrial and the microsomal pathways are multi-component systems bound to these sub-cellular particles, while the remaining enzymes are soluble or readily solubilized proteins. With the exception of the mitochondrial NADH oxidase, which is known to be coupled to the process of oxidative phosphorylation, only scanty information is available on the part played by these oxidative systems. The complexity of mammalian brain presents additional difficulties in attempts to define the biological significance of these enzyme systems.

AN ELECTROPHYSIOLOGICAL STUDY OF THE ANATOMICAL RELATIONS OF TWO GIANT NERVE CELLS IN APLYSIA DEPILANS.

ABSTRACT Histological studies of the central nervous system of invertebrates using methylene-blue and silver-staining techniques, alone or in conjunction with degeneration experiments, have provided a considerable amount of information about neuronal pathways. The use of electrophysiological methods, however, makes it easier to trace the path of individual neurones over long distances and can be especially helpful in invertebrates where the path of an axon is complicated by its passage through the neuropiles. In addition, they may give some insight into the types of functional connexion which exist between neurones.