Development of synapses between identified sensory neurones and giant interneurones in the cockroach Periplaneta americana

Development ◽  
1985 ◽  
Vol 86 (1) ◽  
pp. 227-246
Author(s):  
J. M. Blagburn ◽  
D. J. Beadle ◽  
D. B. Sattelle
Keyword(s):  
Periplaneta Americana ◽  
Synapse Formation ◽  
Primary Dendrite ◽  
Lateral Side ◽  
Synaptic Density ◽  
Sensory Neurones ◽  
Guidance Cues ◽  
First Instar ◽  
Sensory Processes ◽  
Giant Interneurone

The cereal afferent, giant interneurone pathway in Periplaneta americana was used as a model for synapse formation. The morphology of the two identified filiform hair sensory neurones (FHSNs) and of two giant interneurones (GI2 and GI3) was followed throughout embryogenesis by cobalt injection. The FHSN axons enter the CNS at the 45 % stage of embryogenesis, branch at 50 % and form complete arborizations by 70 %. The giant interneurones send out a primary dendrite at 45 %. Secondary branches form between 50 % and 60 % and elaboration of the branching pattern takes place until 80 % embryogenesis. At early stages the FHSN axons are within filopodial range of GI dendrites which may use these sensory processes as guidance cues. Synapse formation between the main FHSN axon shafts and GI dendrites was investigated by injection of the latter with HRP. From 55 % to 65 % the process is initiated by desmosome—like filopodial contacts, with subsequent vesicle clustering and formation of a small synaptic density. Numbers of contacts did not significantly increase after about 70 %, but the number of synapses doubled between 65 % and 75 %, with each GI process becoming postsynaptic to two FHSN synapses and the presynaptic densities lengthening to become bars. From 75 % embryogenesis to hatching there is a further small increase in synaptic bar length. In the first instar GI3 is postsynaptic to both FHSN axons, whereas GI2 forms very few synapses with the axon of the lateral FHSN (LFHSN). This imbalance of contacts is present throughout synaptogenesis, apart from some early filopodial contacts. GI3 forms synapses with the lateral side of the LFHSN axon from 60 % embryogenesis but these are totally absent at hatching. The growth of glia along this side of the axon during the last 30 % of development appears to be associated with degeneration of synapses in this region. Thus, as the dendrites of the GIs grow to form a miniature version of the adult without loss of branches, there is little evidence of an initial overproduction of FHSN—GI synapses. Similarly there is no evidence that GI2 forms ‘incorrect’ synapses with the axon of LFHSN. However, GI3 contacts are removed from an inappropriate region of a correct synaptic partner, LFHSN.

scholarly journals Presynaptic Depolarization Mediates Presynaptic Inhibition at a Synapse Between An Identified Mechanosensory Neurone and Giant Interneurone 3 in the First Instar Cockroach, Periplaneta Americana

1987 ◽  
Vol 127 (1) ◽  
pp. 135-157 ◽  
Author(s):  
JONATHAN M. BLAGBURN ◽  
DAVID B. SATTELLE
Keyword(s):  
Presynaptic Inhibition ◽  
Periplaneta Americana ◽  
Cholinergic Synapse ◽  
Sensory Neurone ◽  
First Instar ◽  
Delayed Rectification ◽  
Intracellular Microelectrodes ◽  
Spike Bursts ◽  
Giant Interneurone ◽  
Filiform Hair

Intracellular microelectrodes were used to study presynaptic inhibition at a cholinergic synapse between identified neurones: the lateral filiform hair sensory neurone (LFHSN) and giant interneurone 3 (GI3) in the terminal ganglion of the first instar cockroach Periplaneta americana. The LFHSN-GI3 synapse was shown to fulfil physiological criteria for monosynaptic transmission: the latency of the EPSPs was 1.4 ms and was constant during high-frequency firing of LFHSN; transmission was progressively and reversibly abolished by replacement of Ca2+ with Mg2+. Movement of the lateral filiform hair towards the cereal tip produced a burst of spikes in LFHSN and a burst of EPSPs in GI 3. Movement of the medial filiform hair towards the base of the cercus produced a burst of spikes in the medial filiform hair sensory neurone (MFHSN) and a burst of EPSPs in GI 2. EPSPs evoked in GI 3 by LFHSN spikes were inhibited during bursts of EPSPs in GI 2 which were evoked by MFHSN spikes. LFHSN was depolarized and its spikes were reduced in amplitude during spike bursts in MFHSN. Reduction in LFHSN spike amplitude reduced GI 3 EPSPs. This phenomenon was attributed, therefore, to presynaptic inhibition. The occurrence of presynaptic inhibition was dependent upon the degree of delayed rectification exhibited by the LFHSN axon. Hyperpolarization of LFHSN increased spike height, but did not increase the amplitude of GI 3 EPSPs. The delay between the onset of MFHSN-evoked EPSPs in GI 2 and MFHSNevoked depolarizations in LFHSN suggested that MFHSN does not synapse directly onto LFHSN. Neither depolarization nor hyperpolarization of GI 2 had any effect on MFHSN-mediated presynaptic inhibition of LFHSN-GI 3 transmission, therefore it was considered unlikely that GI 2 synapses onto LFHSN. Prolonged hyperpolarization lowered the LFHSN spike threshold and temporarily abolished presynaptic inhibition. Bursts of spikes in LFHSN mediated presynaptic inhibition of MFHSN-GI2 EPSPs. Mutual presynaptic inhibition by the FHSNs may have a functional significance in sharpening the boundaries of the GIs' directional sensitivities.

Differential synaptic input of filiform hair sensory neurones on to giant interneurones in the first-instar cockroach

1986 ◽  
Vol 32 (7) ◽  
pp. 591-595 ◽  
Author(s):  
J.M. Blagburn ◽  
D.J. Beadle ◽  
D.B. Sattelle
Keyword(s):  
Synaptic Input ◽  
Sensory Neurones ◽  
First Instar ◽  
Filiform Hair

scholarly journals Thrombospondins 1 and 2 are Necessary for Synaptic Plasticity and Functional Recovery after Stroke

2008 ◽  
Vol 28 (10) ◽  
pp. 1722-1732 ◽  
Author(s):  
Jason Liauw ◽  
Stanley Hoang ◽  
Michael Choi ◽  
Cagla Eroglu ◽  
Matthew Choi ◽  
...  
Keyword(s):  
Infarct Size ◽  
Functional Recovery ◽  
Synapse Formation ◽  
Axonal Sprouting ◽  
Wild Type ◽  
Synaptic Density ◽  
Significant Deficit ◽  
The Common ◽  
Distal Middle Cerebral Artery

Thrombospondins 1 and 2 (TSP-1/2) belong to a family of extracellular glycoproteins with angiostatic and synaptogenic properties. Although TSP-1/2 have been postulated to drive the resolution of postischemic angiogenesis, their role in synaptic and functional recovery is unknown. We investigated whether TSP-1/2 are necessary for synaptic and motor recovery after stroke. Focal ischemia was induced in 8- to 12-week-old wild-type (WT) and TSP-1/2 knockout (KO) mice by unilateral occlusion of the distal middle cerebral artery and the common carotid artery (CCA). Thrombospondins 1 and 2 increased after stroke, with both TSP-1 and TSP-2 colocalizing mostly to astrocytes. Wild-type and TSP-1/2 KO mice were compared in angiogenesis, synaptic density, axonal sprouting, infarct size, and functional recovery at different time points after stroke. Using the tongue protrusion test of motor function, we observed that TSP-1/2 KO mice exhibited significant deficit in their ability to recover function ( P < 0.05) compared with WT mice. No differences were found in infarct size and blood vessel density between the two groups after stroke. However, TSP-1/2 KO mice exhibited significant synaptic density and axonal sprouting deficits. Deficiency of TSP-1/2 leads to impaired recovery after stroke mainly due to the role of these proteins in synapse formation and axonal outgrowth.

Reports of two peculiar pigmented new species of genus Homidia (Collembola: Entomobyridae) from Southern China, with description of subadults chaetotaxy

Zootaxa ◽  
2019 ◽  
Vol 4671 (3) ◽  
pp. 369-380
Author(s):  
ZHI-XIANG PAN ◽  
WAN-QIN YANG
Keyword(s):  
New Species ◽  
Abdominal Segment ◽  
Southern China ◽  
Guangdong Province ◽  
Colour Pattern ◽  
Lateral Side ◽  
First Instar ◽  
Two New Species

Two new species with peculiar pigmentation of the genus Homidia from Guangdong Province, Southern China are described here, Homidia chroma sp. nov. and Homidia leniseta sp. nov. H. chroma is characterized by chrome pigmentation on lateral side of terga, two macrochaetae on medial abdominal segment (Abd.) III and six macrochaetae on postero-medial Abd. IV, up to 68 sensory chaetae present on Abd. IV, and five apical smooth chaetae on posterior face of ventral tube. H. leniseta is easily identified by unique colour pattern, smooth labial chaetae l2, G1–4 and H1–3, and short trichobothria on Abd. II–IV. Illustrations of adults of this two new species, chaetotaxy of the first instar larvae of H. chroma and subadults of H. leniseta are provided herein. 

REPRODUCTIVE BIOLOGY AND LABORATORY REARING OF CERANTHIA SAMARENSIS (VILLENEUVE) (DIPTERA: TACHINIDAE), A PARASITOID OF THE GYPSY MOTH, LYMANTRIA DISPAR (L.)

1993 ◽  
Vol 125 (4) ◽  
pp. 749-759 ◽  
Author(s):  
F.W. Quednau
Keyword(s):  
Gypsy Moth ◽  
Quercus Rubra ◽  
Instar Larva ◽  
The Body ◽  
Lateral Side ◽  
Laboratory Rearing ◽  
First Instar ◽  
Average Longevity ◽  
Gravid Females ◽  
Ceranthia Samarensis

AbstractLaboratory observations on the biology of Ceranthia samarensis (Villeneuve), a tachinid parasitoid of the gypsy moth, were carried out in the laboratory at 22 °C day/15 °C night, 85–90% RH, and a 12L:12D photoperiod. Older (5–6 days post-eclosion) males mated readily with newly emerged females. Mating success was 60%. The gestation period of the mated females was 10–12 days. Laboratory-reared (on diet) second- and third-instar gypsy moth larvae feeding on newly grown foliage of Quercus rubra L. were exposed to gravid females of the parasitoid. Ceranthia samarensis ovolarviposited on the body of the host. The first-instar larva penetrated the host cuticle and developed internally, forming a respiratory funnel that caused a dark circular scar on the lateral side of the caterpillar. The average number of progeny (puparia) produced over the lifetime of a C. samarensis female was 55.0 ± 5.0 (SE) and average longevity was 4.1 ± 1.7 (SE) days. Diapause of the puparia was facultative and induced by temperatures below 20 °C combined with a 12L:12D photoperiod. In nondiapause individuals, total generation time was 22–40 days. To obtain diapause insects, puparia were stored for2monthsat 15 °C, 100% RH, and 12L:12D photoperiod for development of pharate adults. Cold storage at 2–4 °C and 100% RH for at least 5 months was required to obtain up to 75% eclosion after 5–9 days the following year.

scholarly journals Nereistoxin: Actions on a CNS Acetylcholine Receptor/Ion Channel in the Cockroach Periplaneta Americana

1985 ◽  
Vol 118 (1) ◽  
pp. 37-52
Author(s):  
D. B. SATTELLE ◽  
I. D. HARROW ◽  
J. A. DAVID ◽  
M. PELHATE ◽  
J. J. CALLEC ◽  
...  
Keyword(s):  
Ion Channel ◽  
Acetylcholine Receptor ◽  
Periplaneta Americana ◽  
Active Form ◽  
Input Resistance ◽  
Postsynaptic Membrane ◽  
Dependent Manner ◽  
Metathoracic Ganglion ◽  
Voltage Dependent ◽  
Giant Interneurone

Nereistoxin hydrogen oxalate (NTX), at low concentrations (in the range 2.0×10−8-10 × 10−6moll−1), induced a dose-dependent partial block of transmission at cereal afferent, giant interneurone synapses in the terminal abdominal ganglion (A6) of the cockroach Periplaneta americana which was not accompanied by changes in either membrane potential or input resistance of the postsynaptic membrane. At a concentration of 1.0 × 10−7 moll−1, NTX suppressed, in a voltage-dependent manner, acetylcholine-induced currents recorded from voltage-clamped cell bodies of both giant interneurone 2 (GI2) in A6, and the fast coxal depressor motoneurone of the metathoracic ganglion (T3). At higher concentrations (in the range 1.0 × 10−5-1.0 × 10−3moll−1) depolarization of the postsynaptic membrane was observed. Axonal depolarization was noted at concentrations above 1.0 × 10−4moll−1. Voltage-clamp experiments showed that the axonal actions of NTX included suppression of sodium and potassium currents and an increase in the membrane leak current. The concentrations of NTX (in the range 1.0 × 10−5-1.0 × 10−3 moll−1) which show the postsynaptic depolarizing effect are in the same range as the NTX concentrations (l.7 × l0−4 and 6.6 × 10−5moll−1) required for 50% inhibition of the binding of 125I-α-bungarotoxin to Periplaneta abdominal nerve cord extracts and Drosophila head extracts, respectively. Thus a potent, voltage-dependent, blocking action of NTX is detected at the CNS acetylcholine receptor/ion channel complex of the cockroach. This, possibly together with the synaptic and axonal depolarizing effects noted at much higher concentrations, may contribute to the mechanism of action of this natural invertebrate neurotoxin which is also the active form of the synthetic insecticide Cartap.

Imidacloprid actions on insect neuronal acetylcholine receptors

1997 ◽  
Vol 200 (21) ◽  
pp. 2685-2692 ◽  
Author(s):  
S Buckingham ◽  
B Lapied ◽  
H Corronc ◽  
F Sattelle
Keyword(s):  
Nervous System ◽  
Nicotinic Acetylcholine Receptors ◽  
Acetylcholine Receptors ◽  
Periplaneta Americana ◽  
Muscarinic Acetylcholine Receptors ◽  
Nicotinic Acetylcholine ◽  
Neonicotinoid Insecticide ◽  
Dose Dependent ◽  
Dorsal Unpaired Median ◽  
Giant Interneurone

The neonicotinoid insecticide Imidacloprid acts at three pharmacologically distinct acetylcholine receptor (AChR) subtypes in the cockroach (Periplaneta americana) nervous system, but is ineffective on muscarinic receptors. Imidacloprid (3-100&micro;moll-1) induced dose-dependent depolarizations at cockroach cercal afferent/giant interneurone synapses. These responses were insensitive to 20&micro;moll-1 atropine but were completely blocked by the nicotinic antagonist mecamylamine (50&micro;moll-1). Similarly, Imidacloprid-induced depolarizations of cultured cockroach dorsal unpaired median (DUM) neurones dissociated from the same (terminal abdominal) ganglion were also completely blocked by 100&micro;moll-1 mecamylamine. However, two components of the response could be distinguished on the basis of their differential sensitivities to 0.1&micro;moll-1-bungarotoxin (-BTX), which selectively blocks AChRs with 'mixed' nicotinic/muscarinic pharmacology in this preparation. This indicates that Imidacloprid affects both AChRs sensitive to -BTX and -BTX-insensitive nicotinic acetylcholine receptors (nAChRs). Thus, in the cockroach, Imidacloprid activates -BTX-sensitive synaptic nAChRs in giant interneurones, -BTX-insensitive extrasynaptic nAChRs in DUM neurones, and a recently characterized DUM neurone 'mixed' AChR that is sensitive to both nicotinic and muscarinic ligands. Imidacloprid does not act on muscarinic acetylcholine receptors (mAChRs) present on DUM neurone cell bodies and at the cercal afferent/giant interneurone synapses. This study shows that Imidacloprid can act on pharmacologically diverse nAChR subtypes.

Ectopic sensory neurons in mutant cockroaches compete with normal cells for central targets

Development ◽  
1992 ◽  
Vol 115 (3) ◽  
pp. 773-784
Author(s):  
J.P. Bacon ◽  
J.M. Blagburn
Keyword(s):  
Sensory Neurons ◽  
Periplaneta Americana ◽  
Normal Development ◽  
Lateral Position ◽  
Competitive Interactions ◽  
Afferent Neuron ◽  
Synaptic Connections ◽  
First Instar ◽  
Terminal Ganglion ◽  
Filiform Hair

The cercus of the first instar cockroach, Periplaneta americana, bears two filiform hairs, lateral (L) and medial (M), each of which is innervated by a single sensory neuron. These project into the terminal ganglion of the CNS where they make synaptic connections with a number of ascending interneurons. We have discovered mutant animals that have more hairs on the cercus; the most typical phenotype, called “Space Invader” (SI), has an extra filiform hair in a proximo-lateral position on one of the cerci. The afferent neuron of this supernumerary hair (SIN) “invades the space” occupied by L in the CNS and makes similar synaptic connections to giant interneurons (GIs). SIN and L compete for these synaptic targets: the size of the L EPSP in a target interneuron GI3 is significantly reduced in the presence of SIN. Morphometric analysis of the L afferent in the presence or absence of SIN shows no anatomical concomitant of competition. Ablation of L afferent allows SIN to increase the size of its synaptic input to GI3. Less frequently in the mutant population, we find animals with a supernumerary medical (SuM) sensillum. Its afferent projects to the same neuropilar region as the M afferent, makes the same set of synaptic connections to GIs, and competes with M for these synaptic targets. The study of these competitive interactions between identified afferents and identified target interneurons reveals some of the dynamic processes that go on in normal development to shape the nervous system.

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