81 research outputs found
Neuronal background of positioning of the posterior tentacles in the snail Helix pomatia
The location of cerebral neurons innervating the three recently described flexor muscles
involved in the orientation of the posterior tentacles as well as their innervation patterns were
investigated, applying parallel retrograde Co- and Ni-lysine as well as anterograde
neurobiotin tracings via the olfactory and the peritentacular nerves. The neurons are clustered
in eight groups in the cerebral ganglion and they send a common innervation pathway via the
olfactory nerve to the flexor and the tegumental muscles as well as the tentacular retractor
muscle and distinct pathways via the internal and the external peritentacular nerves to these
muscles except the retractor muscle. The three anchoring points of the three flexor muscles at
the base of the tentacle outline the directions of three force vectors generated by the
contraction of the muscles along which they can pull or move the protracted tentacle which
enable the protracted tentacle to bend around a basal pivot. In the light of earlier physiological
and the present anatomical findings we suggest that the common innervation pathway to the
muscles is required to the tentacle withdrawal mechanism whereas the distinct pathways serve
first of all the bending of the protracted posterior tentacles during foraging
The activity of isolated neurons and the modulatory state of an isolated nervous system represent a recent behavioural state
Behavioural/motivational state is known to influence nearly all aspects of physiology and behaviour. The cellular basis of behavioural state control is only partially understood. Our investigation, performed on the pond snail Lymnaea stagnalis whose nervous system is useful for work on completely isolated neurons, provided several results related to this problem. First, we demonstrated that the behavioural state can produce long-term changes in individual neurons that persist even after neuron isolation from the nervous system. Specifically, we found that pedal serotonergic neurons that control locomotion show higher activity and lower membrane potential after being isolated from the nervous systems of hungry animals. Second, we showed that the modulatory state (the chemical neuroactive microenvironment of the central ganglia) changes in accordance with the nutritional state of an animal and produces predicted changes in single isolated locomotor neurons. Third, we report that observed hunger-induced effects can be explained by the increased synthesis of serotonin in pedal serotonergic neurons, which has an impact on the electrical activity of isolated serotonergic neurons and the intensity of extrasynaptic serotonin release from the pedal ganglia
Introduction of the Hungarian Detailed Soil Hydrophysical Database (MARTHA) and its use to test external pedotransfer functions
Noble metal modified (002)-oriented ZnO hollow spheres for the degradation of a broad range of pollutants
Zinc oxide hollow spheres were fabricated by applying sucrose-derived carbon spheres as templates that were
eliminated through calcination. For this purpose, two synthesis methods were examined and compared, chemical
impregnation and solvothermal method. The most suitable ZnO hollow structure was selected for noble metal
deposition (Au and Pt at 1 wt%) to further increase the photocatalytic activity. The photocatalytic activity was
examined by the decomposition of three different model pollutants (phenol, Na-ibuprofen and diuron) under UV
irradiation. The as-synthesized hollow sphere structures and its noble metal composites were further examined
by XRD, SEM, IR, DRS, PL. The templates did not modify the structure of ZnO only the morphology and
contributed to the preservation of the original structure during calcination. The structural, optical and photo-
catalytic activity was correlated with both the application of carbon sphere template, and noble metal deposition
respective their role in the improvement of the photocatalytic activity
Single Mild Traumatic Brain Injury Induces Persistent Disruption of the Blood-Brain Barrier, Neuroinflammation and Cognitive Decline in Hypertensive Rats
Traumatic brain injury (TBI) induces blood-brain barrier (BBB) disruption, which contributes to secondary injury of brain tissue and development of chronic cognitive decline. However, single mild (m)TBI, the most frequent form of brain trauma disrupts the BBB only transiently. We hypothesized, that co-morbid conditions exacerbate persistent BBB disruption after mTBI leading to long term cognitive dysfunction. Since hypertension is the most important cerebrovascular risk factor in populations prone to mild brain trauma, we induced mTBI in normotensive Wistar and spontaneously hypertensive rats (SHR) and we assessed BBB permeability, extravasation of blood-borne substances, neuroinflammation and cognitive function two weeks after trauma. We found that mTBI induced a significant BBB disruption two weeks after trauma in SHRs but not in normotensive Wistar rats, which was associated with a significant accumulation of fibrin and increased neuronal expression of inflammatory cytokines TNFι, IL-1β and IL-6 in the cortex and hippocampus. SHRs showed impaired learning and memory two weeks after mild TBI, whereas cognitive function of normotensive Wistar rats remained intact. Future studies should establish the mechanisms through which hypertension and mild TBI interact to promote persistent BBB disruption, neuroinflammation and cognitive decline to provide neuroprotection and improve cognitive function in patients with mTBI
Cerebral pericytes and endothelial cells communicate through inflammasome-dependent signals
By upregulation of cell adhesion molecules and secretion of proinflammatory cytokines, cells of the neurovascular unit, including pericytes and endothelial cells, actively participate in neuroinflammatory reactions. As previously shown, both cell types can activate inflammasomes, cerebral endothelial cells (CECs) through the canonical pathway, while pericytes only through the noncanonical pathway. Using complex in vitro models, we demonstrate here that the noncanonical inflammasome pathway can be induced in CECs as well, leading to a further increase in the secretion of active interleukin-1β over that observed in response to activation of the canonical pathway. In parallel, a more pronounced disruption of tight junctions takes place. We also show that CECs respond to inflammatory stimuli coming from both the apical/blood and the basolateral/brain directions. As a result, CECs can detect factors secreted by pericytes in which the noncanonical inflammasome pathway is activated and respond with inflammatory activation and impairment of the barrier properties. In addition, upon sensing inflammatory signals, CECs release inflammatory factors toward both the blood and the brain sides. Consequently, CECs activate pericytes by upregulating their expression of NLRP3 (NOD-, LRR-, and pyrin domain-containing protein 3), an inflammasome-forming pattern recognition receptor. In conclusion, cerebral pericytes and endothelial cells mutually activate each other in inflammation
Oxytocin receptor gene polymorphisms are associated with human directed social behavior in dogs (Canis familiaris)
The oxytocin system has a crucial role in human sociality;
several results prove that polymorphisms of the oxytocin
receptor gene are related to complex social behaviors in humans.
Dogs' parallel evolution with humans and their adaptation to the
human environment has made them a useful species to model human
social interactions. Previous research indicates that dogs are
eligible models for behavioral genetic research, as well. Based
on these previous findings, our research investigated
associations between human directed social behaviors and two
newly described (â212AG, 19131AG) and one known (rs8679684)
single nucleotide polymorphisms (SNPs) in the regulatory regions
(5Ⲡand 3ⲠUTR) of the oxytocin receptor gene in German Shepherd
(N = 104) and Border Collie (N = 103) dogs. Dogs' behavior
traits have been estimated in a newly developed test series
consisting of five episodes: Greeting by a stranger, Separation
from the owner, Problem solving, Threatening approach, Hiding of
the owner. Buccal samples were collected and DNA was isolated
using standard protocols. SNPs in the 3Ⲡand 5ⲠUTR regions were
analyzed by polymerase chain reaction based techniques followed
by subsequent electrophoresis analysis. The geneâbehavior
association analysis suggests that oxytocin receptor gene
polymorphisms have an impact in both breeds on (i) proximity
seeking towards an unfamiliar person, as well as their owner,
and on (ii) how friendly dogs behave towards strangers, although
the mediating molecular regulatory mechanisms are yet unknown.
Based on these results, we conclude that similarly to humans,
the social behavior of dogs towards humans is influenced by the
oxytocin system
Fetching what the owner prefers? Dogs recognize disgust and happiness in human behaviour
Monoamines in the pedal plexus of the land snail Megalobulimus oblongus (Gastropoda, Pulmonata)
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