scholarly journals Characterization of developmental changes in spontaneous electrical activity of superior olivary neurons before hearing onset under injectable or volatile anesthesia

2021 ◽  
Author(s):  
Mariano Nicolás Di Guilmi ◽  
Adrián Rodríguez-Contreras
Keyword(s):  
Electrical Activity ◽  
Volatile Anesthetic ◽  
Auditory Brainstem ◽  
Superior Olivary Complex ◽  
Mechanically Ventilated ◽  
Spontaneous Electrical Activity ◽  
Rat Pups ◽  
Auditory Development ◽  
The Impact

AbstractIn this work we studied the impact of two widely used anesthetics on the electrical activity of auditory brainstem neurons during development. The spontaneous electrical activity in neonate rats of either sex was analyzed under the injectable mix of ketamine/xylazine (K/X mix) and the volatile anesthetic isoflurane (ISO). We used a ventral craniotomy in mechanically ventilated pups to carry out electrophysiology recordings in the superior olivary complex (SOC) between birth (postnatal day 0, P0) and P12. To characterize neuronal activity of single and ensembles of neurons, we performed patch clamp and multi-electrode experiments under different anesthetic conditions. Our results provide the first study that compares K/X mix and ISO in the same rodent species. We demonstrate that electrical activity of SOC neurons ramps up during development, and that the firing pattern of single units recorded in K/X mix was similar to that reported in ISO anesthetized rat pups. However, ISO displayed a large scatter on its suppressing effects on electrical activity when delivered at 1.5% in the presence or the absence of K/X mix. Taken together, our results shed light on the use of anesthetics for future studies to enable electrophysiology or optical imaging studies in-vivo to obtain functional information on the activity of medial olivochoclear neurons and their role in auditory development.

scholarly journals Characterization of Developmental Changes in Spontaneous Electrical Activity of Medial Superior Olivary Neurons Before Hearing Onset With a Combination of Injectable and Volatile Anesthesia

2021 ◽  
Vol 15 ◽  
Author(s):  
Mariano Nicolás Di Guilmi ◽  
Adrián Rodríguez-Contreras
Keyword(s):  
Patch Clamp ◽  
Electrical Activity ◽  
Volatile Anesthetic ◽  
Auditory Brainstem ◽  
Superior Olivary Complex ◽  
Medial Region ◽  
Spontaneous Electrical Activity ◽  
Rat Pups ◽  
The Impact

In this work the impact of two widely used anesthetics on the electrical activity of auditory brainstem neurons was studied during postnatal development. Spontaneous electrical activity in neonate rats of either sex was analyzed through a ventral craniotomy in mechanically ventilated pups to carry out patch clamp and multi-electrode electrophysiology recordings in the medial region of the superior olivary complex (SOC) between birth (postnatal day 0, P0) and P12. Recordings were obtained in pups anesthetized with the injectable mix of ketamine/xylazine (K/X mix), with the volatile anesthetic isoflurane (ISO), or in pups anesthetized with K/X mix that were also exposed to ISO. The results of patch clamp recordings demonstrate for the first time that olivary and periolivary neurons in the medial region of the SOC fire bursts of action potentials. The results of multielectrode recordings suggest that the firing pattern of single units recorded in K/X mix is similar to that recorded in ISO anesthetized rat pups. Taken together, the results of this study provide a framework to use injectable and volatile anesthetics for future studies to obtain functional information on the activity of medial superior olivary neurons in vivo.

scholarly journals Lactoferrin Metal Saturation—Which Form Is the Best for Neonatal Nutrition?

Nutrients ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3340
Author(s):  
Grzegorz Majka ◽  
Magdalena Pilarczyk-Zurek ◽  
Agnieszka Baranowska ◽  
Beata Skowron ◽  
Magdalena Strus
Keyword(s):  
Pathogenic Species ◽  
Gram Negative ◽  
Rat Pups ◽  
Gut Homeostasis ◽  
Probiotic Strains ◽  
Neonatal Nutrition ◽  
The Impact ◽  
Iron And Manganese ◽  
Population Numbers

We evaluated the impact of metal saturation of lactoferrin (with iron and manganese) on population numbers of pathogenic species relevant for neonatal sepsis that commonly originates from the gut due to bacterial translocation. Little attention has been paid to how metal ions bound to the protein affect its activity. Several reference and clinical strains as well as probiotic strains were incubated with different forms of lactoferrin: metal-depleted (apolactoferrin), iron-saturated (hololactoferrin) and manganese-saturated lactoferrin. We also attempted to confirm the observed effects of lactoferrin forms in vivo using rat pups. The observed decrease in population numbers of Gram-negative rods could not be confirmed by quantitative plating—lactoferrin may regulate these populations diversely (e.g., by anti-biofilm activity) and contribute to the inhibition of inflammatory response. We did not see any effect of lactoferrin forms on staphylococci and bifidobacteria. However, we have noted a significant increase of population numbers of Lactobacillus strains upon incubation with manganese-saturated lactoferrin. These results were confirmed in vivo in a rat model. Metal saturation is an underestimated factor regulating lactoferrin activity. Some forms are more potent in the inhibition of pathogenic species while others, such as manganese-saturated lactoferrin, could contribute to the restoration of gut homeostasis.

Aging Processes in the Subcortical Auditory System

2018 ◽  
pp. 638-680 ◽  
Author(s):  
Donald M. Caspary ◽  
Daniel A. Llano
Keyword(s):  
Hearing Loss ◽  
Auditory System ◽  
De Novo ◽  
Auditory Brainstem ◽  
Superior Olivary Complex ◽  
Age Related ◽  
Medial Geniculate ◽  
Age Related Hearing Loss ◽  
The Impact ◽  
Age Related Changes

As arguably the third most common malady of industrialized populations, age-related hearing loss is associated with social isolation and depression in a subset of the population that will approach 25% by 2050. Development of behavioral or pharmacotherapeutic approaches to prevent or delay the onset of age-related hearing loss and mitigate the impact of hearing loss of speech understanding requires a better understanding of age-related changes that occur in the central auditory processor. This chapter critically reviews and discusses changes that occur in the auditory brainstem and thalamus with increased age. It briefly discusses age-related cellular changes that occur de novo within the central auditory system versus deafferentation plasticity and animal models of aging. Subsections discuss the cochlear nucleus, superior olivary complex, inferior colliculus, and the medial geniculate body with an emphasis on age-related changes in neurotransmission and how these changes could underpin the observed loss of precise temporal processing with increased age.

scholarly journals Resistance to action potential depression of a rat axon terminal in vivo

2017 ◽  
Vol 114 (16) ◽  
pp. 4249-4254 ◽  
Author(s):  
Martijn C. Sierksma ◽  
J. Gerard G. Borst
Keyword(s):  
Membrane Potential ◽  
Action Potential ◽  
Auditory Brainstem ◽  
Strong Impact ◽  
Fast Recovery ◽  
Calyx Of Held ◽  
Onset Potential ◽  
Rat Pups ◽  
The Central Nervous System

The shape of the presynaptic action potential (AP) has a strong impact on neurotransmitter release. Because of the small size of most terminals in the central nervous system, little is known about the regulation of their AP shape during natural firing patterns in vivo. The calyx of Held is a giant axosomatic terminal in the auditory brainstem, whose biophysical properties have been well studied in slices. Here, we made whole-cell recordings from calyceal terminals in newborn rat pups. The calyx showed a characteristic burst firing pattern, which has previously been shown to originate from the cochlea. Surprisingly, even for frequencies over 200 Hz, the AP showed little or no depression. Current injections showed that the rate of rise of the AP depended strongly on its onset potential, and that the membrane potential after the AP (Vafter) was close to the value at which no depression would occur during high-frequency activity. Immunolabeling revealed that Nav1.6 is already present at the calyx shortly after its formation, which was in line with the fast recovery from AP depression that we observed in slice recordings. Our findings thus indicate that fast recovery from depression and an inter-AP membrane potential that minimizes changes on the next AP in vivo, together enable high timing precision of the calyx of Held already shortly after its formation.

scholarly journals CONTINUOUS OBSERVATIONS OF SPONTANEOUS ELECTRICAL ACTIVITY OF THE NONPREGNANT UTERUS OF RAT IN VIVO

1968 ◽  
Vol 4 (1) ◽  
pp. 37-45
Author(s):  
Hosuke SUDA ◽  
Kyushiro FUJII ◽  
Kazuo ARAI ◽  
Riichi MARUOKA ◽  
Jintaka SAITO
Keyword(s):  
Electrical Activity ◽  
Spontaneous Electrical Activity

scholarly journals CONTINUOUS OBSERVATIONS OF SPONTANEOUS ELECTRICAL ACTIVITY OF THE PREGNANT UTERUS OF RAT IN VIVO

1968 ◽  
Vol 4 (2) ◽  
pp. 191-202
Author(s):  
Hosuke SUDA ◽  
Kyushiro FUJII ◽  
Kazuo ARAI ◽  
Riichi MARUOKA ◽  
Jintaka SAITO
Keyword(s):  
Electrical Activity ◽  
Pregnant Uterus ◽  
Spontaneous Electrical Activity

In vivo recording of electrical activity of canine tracheal smooth muscle

1992 ◽  
Vol 72 (1) ◽  
pp. 135-142 ◽  
Author(s):  
T. Kondo ◽  
K. Tamura ◽  
K. Onoe ◽  
H. Takahira ◽  
Y. Ohta ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Electrical Activity ◽  
Slow Wave ◽  
Oscillatory Potentials ◽  
Tracheal Smooth Muscle ◽  
Lung Collapse ◽  
Mechanically Ventilated ◽  
Bipolar Electrodes ◽  
Fast Spike

Electrical activity of the tracheal smooth muscle was studied using extracellular bipolar electrodes in 37 decerebrate, paralyzed, and mechanically ventilated dogs. A spontaneous oscillatory potential that consisted of a slow sinusoidal wave of 0.57 +/- 0.13 (SD) Hz mean frequency but lacked a fast spike component was recorded from 15 dogs. Lung collapse accomplished by bilateral pneumothoraxes evoked or augmented the slow potentials that were associated with an increase in tracheal muscle contraction in 26 dogs. This suggests that the inputs from the airway mechanoreceptors reflexly activate the tracheal smooth muscle cells. Bilateral vagal transection abolished both the spontaneous and the reflexly evoked slow waves and provided relaxation of the tracheal smooth muscle. Electrical stimulation of the distal nerve with a train pulse (0.5 ms, 1–30 Hz) evoked slow-wave oscillatory potentials accompanied by a contraction of the tracheal smooth muscle in all the experimental animals. Our observations in this in vivo study confirm that the electrical activity of tracheal smooth muscle consists of slow oscillatory potentials and that tracheal contraction is at least partly coupled to the slow-wave activity of the smooth muscle.

Measurement of spontaneous neuronal membrane activity by time lapse confocal microscopy

1995 ◽  
Vol 53 ◽  
pp. 972-973
Author(s):  
R H. Selinfreund ◽  
A. H. Cornell-Bell
Keyword(s):  
Membrane Potential ◽  
Confocal Microscopy ◽  
Patch Clamp ◽  
Electrical Activity ◽  
Time Lapse ◽  
Neuronal Firing ◽  
Neuronal Membrane ◽  
Pituitary Cells ◽  
Patch Clamp Recording ◽  
Spontaneous Electrical Activity

Cellular electrophysiological properties are normally monitored by standard patch clamp techniques . The combination of membrane potential dyes with time-lapse laser confocal microscopy provides a more direct, least destructive rapid method for monitoring changes in neuronal electrical activity. Using membrane potential dyes we found that spontaneous action potential firing can be detected using time-lapse confocal microscopy. Initially, patch clamp recording techniques were used to verify spontaneous electrical activity in GH4\C1 pituitary cells. It was found that serum depleted cells had reduced spontaneous electrical activity. Brief exposure to the serum derived growth factor, IGF-1, reconstituted electrical activity. We have examined the possibility of developing a rapid fluorescent assay to measure neuronal activity using membrane potential dyes. This neuronal regeneration assay has been adapted to run on a confocal microscope. Quantitative fluorescence is then used to measure a compounds ability to regenerate neuronal firing.The membrane potential dye di-8-ANEPPS was selected for these experiments. Di-8- ANEPPS is internalized slowly, has a high signal to noise ratio (40:1), has a linear fluorescent response to change in voltage.

Experimental Study of the Impact of Alisma plantago-aquatica Secretions on Pathogenic Bacteria

2014 ◽  
Vol 1 (3) ◽  
pp. 3-7
Author(s):  
O. Zhukorskyy ◽  
O. Hulay
Keyword(s):  
Pathogenic Bacteria ◽  
Initial Density ◽  
Biologically Active ◽  
Erysipelothrix Rhusiopathiae ◽  
Natural Focus ◽  
Test Species ◽  
Popula Tions ◽  
And Control ◽  
The Impact

Aim. To estimate the impact of in vivo secretions of water plantain (Alisma plantago-aquatica) on the popula- tions of pathogenic bacteria Erysipelothrix rhusiopathiae. Methods. The plants were isolated from their natural conditions, the roots were washed from the substrate residues and cultivated in laboratory conditions for 10 days to heal the damage. Then the water was changed; seven days later the selected samples were sterilized using fi lters with 0.2 μm pore diameter. The dilution of water plantain root diffusates in the experimental samples was 1:10–1:10,000. The initial density of E. rhusiopathiae bacteria populations was the same for both experimental and control samples. The estimation of the results was conducted 48 hours later. Results. When the dilution of root diffusates was 1:10, the density of erysipelothrixes in the experimental samples was 11.26 times higher than that of the control, on average, the dilution of 1:100 − 6.16 times higher, 1:1000 – 3.22 times higher, 1:10,000 – 1.81 times higher, respectively. Conclusions. The plants of A. plantago-aquatica species are capable of affecting the populations of E. rhusiopathiae pathogenic bacteria via the secretion of biologically active substances into the environment. The consequences of this interaction are positive for the abovementioned bacteria, which is demon- strated by the increase in the density of their populations in the experiment compared to the control. The intensity of the stimulating effect on the populations of E. rhusiopathiae in the root diffusates of A. plantago-aquatica is re- ciprocally dependent on the degree of their dilution. The investigated impact of water plantain on erysipelothrixes should be related to the topical type of biocenotic connections, the formation of which between the test species in the ecosystems might promote maintaining the potential of natural focus of rabies. Keywords: Alisma plantago-aquatica, in vivo secretions, Erysipelothrix rhusiopathiae, population density, topical type of connections.

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