Physiology of Morphologically Identified Cells in the Posterior Caudal Lobe of the Mormyrid Cerebellum

2007 ◽  
Vol 98 (3) ◽  
pp. 1297-1308 ◽  
Author(s):  
Yueping Zhang ◽  
Victor Z. Han
Keyword(s):  
Purkinje Cells ◽  
Physiological Responses ◽  
Slice Preparation ◽  
Parallel Fibers ◽  
Caudal Lobe ◽  
Electrosensory System ◽  
Synaptic Inputs ◽  
Mormyrid Fish ◽  
Similarities And Differences

The cerebellum of the mormyrid fish consists of three major divisions: the valvula, the central lobes, and the caudal lobes. Several studies have focused on the central lobes and the valvula, but little is known about the caudal lobes. The mormyrid caudal lobe includes anterior and posterior components. The anterior caudal lobe is associated with the lateral line and eighth nerve end organs, whereas the posterior caudal lobe is associated with the electrosensory system. The present study examines the physiology and pharmacology of morphologically identified Purkinje cells and efferent cells in an in vitro slice preparation of the posterior caudal lobe. We found that the Purkinje cells in the posterior caudal lobe can be classified into three subtypes based on both their morphology and on their physiological responses to intracellular current injection and to synaptic inputs from parallel fibers and climbing fibers. Similarities and differences between the physiology of the caudal lobe and that of other regions of the mormyrid cerebellum and the mammalian cerebellum are discussed.

scholarly journals Sensory processing and corollary discharge effects in posterior caudal lobe Purkinje cells in a weakly electric mormyrid fish

2014 ◽  
Vol 112 (2) ◽  
pp. 328-339 ◽  
Author(s):  
Karina Alviña ◽  
Nathaniel B. Sawtell
Keyword(s):  
Purkinje Cells ◽  
Mossy Fiber ◽  
Corollary Discharge ◽  
Electrophysiological Response ◽  
Caudal Lobe ◽  
Mormyrid Fish ◽  
Sensory Structures ◽  
Proprioceptive Inputs ◽  
Weakly Electric ◽  
Complete Account

Although it has been suggested that the cerebellum functions to predict the sensory consequences of motor commands, how such predictions are implemented in cerebellar circuitry remains largely unknown. A detailed and relatively complete account of predictive mechanisms has emerged from studies of cerebellum-like sensory structures in fish, suggesting that comparisons of the cerebellum and cerebellum-like structures may be useful. Here we characterize electrophysiological response properties of Purkinje cells in a region of the cerebellum proper of weakly electric mormyrid fish, the posterior caudal lobe (LCp), which receives the same mossy fiber inputs and projects to the same target structures as the electrosensory lobe (ELL), a well-studied cerebellum-like structure. We describe patterns of simple spike and climbing fiber activation in LCp Purkinje cells in response to motor corollary discharge, electrosensory, and proprioceptive inputs and provide evidence for two functionally distinct Purkinje cell subtypes within LCp. Protocols that induce rapid associative plasticity in ELL fail to induce plasticity in LCp, suggesting differences in the adaptive functions of the two structures. Similarities and differences between LCp and ELL are discussed in light of these results.

scholarly journals Cell type-specific plasticity at parallel fiber synapses onto Purkinje cells in the posterior caudal lobe of the mormyrid fish cerebellum

2018 ◽  
Vol 120 (2) ◽  
pp. 644-661
Author(s):  
Yueping Zhang ◽  
Gerhard Magnus ◽  
Victor Z. Han
Keyword(s):  
Purkinje Cells ◽  
Cell Types ◽  
Long Term Potentiation ◽  
Cell Type ◽  
Long Term Depression ◽  
Caudal Lobe ◽  
Term Potentiation ◽  
Mormyrid Fish ◽  
Cell Type Specific

It has been demonstrated that there are two morphological subtypes of Purkinje cells (PCs)—fan-shaped Purkinje cells (fPCs) and multipolar Purkinje cells (mPCs)—in the posterior caudal lobe of the mormyrid fish cerebellum, but whether these cell types are also functionally distinct is unknown. Here, we have used electrophysiological and pharmacological tools in a slice preparation to demonstrate that pairing parallel fiber (PF) and climbing fiber (CF) inputs at a low frequency induces long-term depression (LTD) in fPCs but long-term potentiation (LTP) in mPCs. The induction of plasticity in both cell types required postsynaptic Ca2+ and type 1α metabotropic glutamate receptors. However, the LTD in fPCs was inducted via a calcium/calmodulin-dependent protein kinase II cascade, whereas LTP induction in mPCs required calcineurin. Moreover, the LTD in fPCs and LTP in mPCs were accompanied by changes to the corresponding paired-pulse ratios and their coefficients of variation, suggesting presynaptic modes of expression for the plasticity at PF terminals for both cell types. Hence, the synaptic plasticity at PF synapses onto PCs in the posterior caudal lobe of the mormyrid cerebellum is cell type specific, with both pre- and postsynaptic mechanisms contributing to its induction and expression. NEW & NOTEWORTHY Much has been learnt about the cerebellar long-term depression (LTD) in the cortex. More recent work has shown that long-term potentiation (LTP) is equally important for cerebellar motor learning. Here we report for the first time that plasticity in the mormyrid cerebellum is cell type specific, e.g., following the conventional pairing of parallel and climbing fiber inputs in an in vitro preparation leads to LTD in one Purkinje cell subtype and LTP in another.

scholarly journals In vitro Osmotic Stress Memory in Chrisanthemum hybridum: Structural and Physiological Responses

2017 ◽  
Vol 27 (2) ◽  
pp. 161-169 ◽  
Author(s):  
Lidiia Samarina ◽  
Valentina Malyarovskaya ◽  
Yulija Abilfazova ◽  
Natalia Platonova ◽  
Kristina Klemeshova ◽  
...  
Keyword(s):  
Osmotic Stress ◽  
Relative Water Content ◽  
Soluble Protein ◽  
Growth Parameters ◽  
Physiological Responses ◽  
Proline Content ◽  
Stress Exposure ◽  
Stress Memory ◽  
Relative Water

Structural and physiological responses of chrysanthemum to repeated osmotic stress were studied. Plants were cultured for 2 weeks (for each stress1 and stress 2) on half MS supplemented with mannitol 100 mM (Treatment I) and 200 mM (Treatment II). First stress inhibited growth parameters stronger than second stress in treatment I. In treatment II both stress events strongly inhibited growth parameters of micro‐shoots. Proline content exceeded control 6 ‐ 8 times after 1st stress, and 2 ‐ 5 times after the 2nd stress in treatments I and II, respectively. Soluble protein was accumulated in leaves during both stress exposures, and 2 ‐ 2.5 times exceeded control after the 2nd stress. Relative water content in both treatments increased after the 2nd stress exposure. In treatment II chlorophyll а and carotenoids contents were 8.78 and 4.62 mg/g comparing to control (4.21 and 2.25 mg/g, respectively) after the 1st stress. But after the 2nd stress there was no difference with control.Plant Tissue Cult. & Biotech. 27(2): 161-169, 2017 (December)

scholarly journals Rheological and Microstructural Features of Plant Culture Media Doped with Biopolymers: Influence on the Growth and Physiological Responses of In Vitro-Grown Shoots of Thymus lotocephalus

2021 ◽  
Vol 2 (2) ◽  
pp. 538-553
Author(s):  
Natacha Coelho ◽  
Alexandra Filipe ◽  
Bruno Medronho ◽  
Solange Magalhães ◽  
Carla Vitorino ◽  
...  
Keyword(s):  
In Vitro Culture ◽  
Culture Medium ◽  
Culture Media ◽  
Average Pore Size ◽  
Physiological Responses ◽  
Gum Arabic ◽  
Shoot Elongation ◽  
Hydroxyethyl Cellulose ◽  
Plant Culture

In vitro culture is an important biotechnological tool in plant research and an appropriate culture media is a key for a successful plant development under in vitro conditions. The use of natural compounds to improve culture media has been growing and biopolymers are interesting alternatives to synthetic compounds due to their low toxicity, biodegradability, renewability, and availability. In the present study, different culture media containing one biopolymer (chitosan, gum arabic) or a biopolymer derivative [hydroxyethyl cellulose (HEC), carboxymethyl cellulose (CMC)], at 100 or 1000 mg L−1, were tested regarding their influence on the growth and physiological responses of Thymus lotocephalus in vitro culture. Cellulose-based biopolymers (HEC and CMC) and gum arabic were used for the first time in plant culture media. The results showed that CMC at 100 mg L−1 significantly improved shoot elongation while chitosan, at the highest concentration, was detrimental to T. lotocephalus. Concerning only the evaluated physiological parameters, all tested biopolymers and biopolymer derivatives are safe to plants as there was no evidence of stress-induced changes on T. lotocephalus. The rheological and microstructural features of the culture media were assessed to understand how the biopolymers and biopolymer derivatives added to the culture medium could influence shoot growth. As expected, all media presented a gel-like behaviour with minor differences in the complex viscosity at the beginning of the culture period. Most media showed increased viscosity overtime. The surface area increased with the addition of biopolymers and biopolymer derivatives to the culture media and the average pore size was considerably lower for CMC at 100 mg L−1. The smaller pores of this medium might be related to a more efficient nutrients and water uptake by T. lotocephalus shoots, leading to a significant improvement in shoot elongation. In short, this study demonstrated that the different types of biopolymers and biopolymer derivatives added to culture medium can modify their microstructure and at the right concentrations, are harmless to T. lotocephalus shoots growing in vitro, and that CMC improves shoot length.

scholarly journals MICROSPECTROPHOTOMETRY OF NEWLY SYNTHESIZED STARCH IN SITU

1970 ◽  
Vol 18 (6) ◽  
pp. 439-449
Author(s):  
GEORGE E. WHEELER
Keyword(s):  
Absorption Maximum ◽  
In Vitro Studies ◽  
Phosphate Solution ◽  
Starch Digestion ◽  
Spectral Curves ◽  
Similarities And Differences

Many of the cells in stem sections of several Commelinaceae species synthesized much new starch when incubated in buffered 1% glucose 1-phosphate solution. The starch appeared in the cytoplasm rather than in the plastids. Although the starch I2-KI color was uniform within any one cell, there was considerable variation from cell to cell, even in the same section. The colors with I2-KI ranged from blue, through purples to magenta and mahogany. Tests with α-amylase and with β-amylase showed the starch to be amylose. Microspectrophotometrically determined extinction curves, based on the new starch in situ, varied with the visualized color. As expected, starch which stained blue with I2-KI had an absorption maximum in the orange-red wavelengths above 600 mµ; increasingly red I2-KI colors were characterized by shifts of the absorption maximum further into the shorter wavelengths. The course of new starch digestion by α-amylase and by β-amylase was followed visually and with the microspectrophotometer. Similarities and differences between these spectral curves and those published for in vitro studies are pointed out. The difficulties met with in using the microspectrophotometric method are discussed.

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