scholarly journals Direct inhibition of histamine receptors in the antennal lobe of Manduca sexta: Putative evidence for an olfactory corollary discharge circuit

2016 ◽  
Author(s):  
Rex Burkland
Keyword(s):  
Manduca Sexta ◽  
Antennal Lobe ◽  
Histamine Receptors ◽  
Corollary Discharge ◽  
Discharge Circuit ◽  
Direct Inhibition

Olfactory activation patterns in the antennal lobe of the sphinx moth, Manduca sexta

2003 ◽  
Vol 189 (4) ◽  
pp. 301-308 ◽  
Author(s):  
B. S. Hansson ◽  
M. A. Carlsson ◽  
B. Kalinovà
Keyword(s):  
Manduca Sexta ◽  
Antennal Lobe ◽  
Activation Patterns

Plateau Potentials in Developing Antennal-Lobe Neurons of the Moth, Manduca sexta

2005 ◽  
Vol 93 (4) ◽  
pp. 1949-1958 ◽  
Author(s):  
A. R. Mercer ◽  
P. Kloppenburg ◽  
J. G. Hildebrand
Keyword(s):  
Electrical Activity ◽  
Manduca Sexta ◽  
Antennal Lobe ◽  
Membrane Properties ◽  
Plateau Potentials ◽  
Extracellular Medium ◽  
Threshold Phenomena ◽  
Plateau State ◽  
Developing Neurons

Using whole cell recordings from antennal-lobe (AL) neurons in vitro and in situ, in semi-intact brain preparations, we examined membrane properties that contribute to electrical activity exhibited by developing neurons in primary olfactory centers of the brain of the sphinx moth, Manduca sexta. This activity is characterized by prolonged periods of membrane depolarization that resemble plateau potentials. The presence of plateau potential–generating mechanisms was confirmed using a series of tests established earlier. Brief depolarizing current pulses could be used to trigger a plateau state. Once triggered, plateau potentials could be terminated by brief pulses of hyperpolarizing current. Both triggering and terminating of firing states were threshold phenomena, and both conditions resulted in all-or-none responses. Rebound excitation from prolonged hyperpolarizing pulses could also be used to generate plateau potentials in some cells. These neurons were found to express a hyperpolarization-activated inward current. Neither the generation nor the maintenance of plateau potentials was affected by removal of Na+ ions from the extracellular medium or by blockade of Na+ currents with TTX. However, blocking of Ca2+ currents with Cd2+ (5 × 10−4 M) inhibited the generation of plateau potentials, indicating that, in Manduca AL neurons, plateau potentials depend on Ca2+. Examining Ca2+ currents in isolation revealed that activation of these currents occurs in the absence of experimentally applied depolarizing stimuli. Our results suggest that this activity underlies the generation of plateau potentials and characteristic bursts of electrical activity in developing AL neurons of M. sexta.

Organization and synaptic ultrastructure of glomeruli in the antennal lobes of the moth Manduca sexta : a study using thin sections and freeze-fracture

1981 ◽  
Vol 213 (1192) ◽  
pp. 279-301 ◽  
Keyword(s):  
Manduca Sexta ◽  
Antennal Lobe ◽  
Freeze Fracture ◽  
Central Area ◽  
Presynaptic Membrane ◽  
Thin Sections ◽  
Large Numbers ◽  
Synaptic Ultrastructure ◽  
Large Particles ◽  
Antennal Nerve

The antennal lobe of the brain of Manduca sexta comprises a central area of coarse neuropil surrounded by dense, spheroidal glomeruli, where all synaptic interactions between antennal-nerve axons and the second-order neurons of the lobe occur. Neuronal interactions in the glomeruli are complex, involving several types of neuritic profiles and mediated by synapses with a one-to-many ratio of pre- to postsynaptic elements. Presynaptic profiles in the glomeruli have been categorized into three types, containing round clear vesicles, large numbers of large dense-cored vesicles, and pleiomorphic clear vesicles, respectively. Preliminary studies of horseradish peroxidase-filled axons and neurons indicate that antennal-nerve axons form synapses without large numbers of dense-cored vesicles and that antennal-lobe neurons not only receive synapses but also may synapse onto other elements in the antennal lobe. A typical synaptic contact involves multiple postsynaptic elements apposed in pairs to an individual presynaptic element. The presynaptic element contains a bar-shaped membrane-associated density, which follows a shallow groove in the membrane and is flanked by synaptic vesicles. Postsynaptic elements are lined by membrane-associated densities in the region opposite to the synaptic bar, and may be observed to participate in serial synapses. Freeze-fracture replicas of the glomerular neuropil contain many membrane specializations that are thought to be presynaptic, some of which resemble those of vertebrate excitatory synapses. At these apparently presynaptic regions, large particles cluster in the P face of the membrane and are often surrounded by plasmalemmal deformations presumably representing sites of exo- or endocytosis. The shape of the predominant type of presynaptic membrane specialization (a plaque) does not match the shape of the presynaptic membrane-associated density (a bar); this raises the possibility that vesicle release occurs at isolated ‘active zones’ along the presynaptic bar. Postsynaptic sites are represented by clusters of large particles in the E face of the postsynaptic membrane.

Modulatory effects of 5-hydroxytryptamine on voltage-activated currents in cultured antennal lobe neurones of the sphinx moth Manduca sexta.

1995 ◽  
Vol 198 (3) ◽  
pp. 613-627 ◽  
Author(s):  
A R Mercer ◽  
J H Hayashi ◽  
J G Hildebrand
Keyword(s):  
Manduca Sexta ◽  
Adult Development ◽  
Antennal Lobe ◽  
Ionic Currents ◽  
Delayed Rectifier ◽  
Patch Clamp Recording ◽  
Whole Cell Patch Clamp ◽  
K Current ◽  
Reversible Reduction

The modulatory effects of 5-hydroxytryptamine (5-HT or serotonin) on voltage-gated currents in central olfactory neurones of the moth Manduca sexta have been examined in vitro using whole-cell patch-clamp recording techniques. Central olfactory neurones were dissociated from the antennal lobes of animals at stage 5 of the 18 stages of metamorphic adult development. The modulatory actions of 5-HT on voltage-activated ionic currents were examined in a subset of morphologically identifiable antennal lobe neurones maintained for 2 weeks in primary cell culture. 5-HT caused reversible reduction of both a rapidly activating A-type K+ current and a relatively slowly activating K+ current resembling a delayed rectifier-type conductance. 5-HT also reduced the magnitude of voltage-activated Ca2+ influx in these cells. The functional significance of 5-HT-modulation of central neurones is discussed.

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