Comparative transduction mechanisms of hair cells in the bullfrog utriculus. II. Sensitivity and response dynamics to hair bundle displacement

1994 ◽  
Vol 71 (2) ◽  
pp. 685-705 ◽  
Author(s):  
R. A. Baird
Keyword(s):  
Hair Cells ◽  
Linear Displacement ◽  
Linear Range ◽  
Hair Bundle ◽  
Morphological Data ◽  
C Cells ◽  
Type B ◽  
Response Dynamics ◽  
Displacement Response ◽  
Type C

1. Hair cells in whole-mount in vitro preparations of the utricular macula of the bullfrog (Rana catesbeiana) were selected according to their macular location and hair bundle morphology. The sensitivity and response dynamics of selected hair cells to natural stimulation were examined by recording their voltage responses to step and sinusoidal hair bundle displacements applied to their longest stereocilia. 2. The voltage responses of 31 hair cells to sinusoidal hair bundle displacements were characterized by their gains and phases, taken with respect to peak hair bundle displacement. The gains of Type B and Type C cells at both 0.5 and 5.0 Hz were markedly lower than those of Type F and Type E cells. Phases, with the exception of Type C cells, lagged hair bundle displacement at 0.5 Hz. Type C cells had phase leads of 25-40 degrees. At 5.0 Hz, response phases in all cells were phase lagged with respect to those at 0.5 Hz. Type C cells had larger gains and smaller phase leads at 5.0 Hz than at 0.5 Hz, suggesting the presence of low-frequency adaptation. 3. Displacement-response curves, derived from the voltage responses to 5.0-Hz sinusoids, were sigmoidal in shape and asymmetrical, with the depolarizing response having a greater magnitude and saturating less abruptly than the hyperpolarizing response. When normalized to their largest displacement the linear ranges of these curves varied from < 0.5 to 1.25 microns and were largest in Type B and smallest in Type F and Type E cells. Sensitivity, defined as the slope of the normalized displacement-response curve, was inversely correlated with linear range. 4. The contribution of geometric factors associated with the hair bundle to linear range and sensitivity were predicted from realistic models of utricular hair bundles created using morphological data obtained from light and electron microscopy. Three factors, including 1) the inverse ratio of the lengths of the kinocilium and longest stereocilia, representing the lever arm between kinociliary and stereociliary displacement; 2) tip link extension/linear displacement, largely a function of stereociliary height and separation; and 3) stereociliary number, an estimate of the number of transduction channels, were considered in this analysis. The first of these factors was quantitatively more important than the latter two factors and their total contribution was largest in Type B and Type C cells. Theoretical models were also used to calculate the relation between rotary and linear displacement.(ABSTRACT TRUNCATED AT 400 WORDS)

Comparative transduction mechanisms of hair cells in the bullfrog utriculus. I. Responses to intracellular current

1994 ◽  
Vol 71 (2) ◽  
pp. 666-684 ◽  
Author(s):  
R. A. Baird
Keyword(s):  
B Cells ◽  
Hair Cell ◽  
Hair Cells ◽  
Hair Bundle ◽  
C Cells ◽  
Type B ◽  
Lateral Border ◽  
Utricular Macula ◽  
Type C ◽  
Current Steps

1. Hair cells in whole-mount in vitro preparations of the utricular macula of the bullfrog (Rana catesbeiana) were selected according to their macular location and hair bundle morphology. The voltage responses of selected hair cells to intracellular current steps and sinusoids in the frequency range of 0.5-200 Hz were studied with conventional intracellular recordings. 2. The utricular macula is divided into medial and lateral parts by the striola, a 75- to 100-microns zone that runs for nearly the entire length of the sensory macula near its lateral border. The striola is distinguished from flanking extrastriolar regions by the elevated height of its apical surface and the wider spacing of its hair cells. A line dividing hair cells of opposing polarities, located near the lateral border of the striola, separates it into medial and lateral parts. On average, the striola consists of five to seven medial and two to three lateral rows of hair cells. 3. Utricular hair cells were classified into four types on the basis of hair bundle morphology. Type B cells, the predominant hair cell type in the utricular macula, are small cells with short sterocilia and kinocilia 2-6 times as long as their longest stereocilia. These hair cells were found throughout the extrastriola and, more rarely, in the striolar region. Three other hair cell types were restricted to the striolar region. Type C cells, found primarily in the outer striolar rows, resemble enlarged versions of Type B hair cells. Type F cells have kinocilia approximately equal in length to their longest stereocilia and are restricted to the middle striolar rows. Type E cells, found only in the innermost striolar rows, have short kinocilia with prominent kinociliary bulbs. 4. The resting potential of 99 hair cells was -58.0 +/- 7.6 (SD) mV and did not vary significantly for hair cells in differing macular locations or with differing hair bundle morphology. The RN of hair cells, measured from the voltage response to current steps, varied from 200 to > 2,000 M omega and was not well correlated with cell size. On average, Type B cells had the highest RN, followed by Type F, Type E, and Type C cells. When normalized to their surface area, the membrane resistance of hair cells ranged from < 1,000 to > 10,000 k omega.cm2. The input capacitance of hair cells ranged from < 3 to > 15 pA, corresponding on average to a membrane capacitance of 0.8 +/- 0.2 pA/cm2.(ABSTRACT TRUNCATED AT 400 WORDS)

Structural changes, related to reproduction, in the hypothalamus and in the pars tuberalis of the rhesus monkey: Part I. The hypothalamus. Part II. The pars tuberalis

1969 ◽  
Vol 256 (809) ◽  
pp. 357-375 ◽  
Keyword(s):  
Menstrual Cycle ◽  
Rhesus Monkey ◽  
Blood Vessels ◽  
Median Eminence ◽  
Pars Tuberalis ◽  
C Cells ◽  
Type B ◽  
Iii Ventricle ◽  
Type C ◽  
The Brain

Certain cells lining a circumscribed area of the III ventricle of the rhesus monkey differ from those cells which constitute the characteristic ependymal lining of the brain. The specialized cells studied comprise a number of types which differ in their structure, ultrastructure and staining affinities; all demonstrate features which are generally associated with active secretion and/or absorption. A group of such cells, which form a limited area of the latero-ventral walls of the anterior hypothalamus, have long processes which extend to the walls of the blood vessels in the median eminence. The evidence indicates that many of these cells, here described as Type B or tanycyte cells, secrete their products into the primary capillary network of the pituitary portal system. Another group of cells, here described as Type C and C' cells are found in a slightly more posterior position lining the floor of the ventricle; as yet there are no indications that these may secrete into blood vessels in the median eminence. Some of the specialized cells lining the III ventricle (Types B and C') showed changes in relation to reproductive activity: No such changes were observed in Type C cells nor in the characteristic ependymal cells (Type A) found elsewhere. Studies on normal and experimental male and female monkeys showed that Type B tanycyte cells differed in males and females and altered during the menstrual cycle in the female. Following ovariectomy these cells showed regressive changes but returned to a normal appearance after a single injection of oestradiol. In view of the close spatial relationship of the tanycyte ependyma to cells of the pars tuberalis it was interesting to note that pars tuberalis cells also altered in relation to the menstrual cycle. The evidence presented accords with the view that certain cells which line the III ventricle of the brain and have prolongations extending to pituitary blood vessels, thus linking the cerebrospinal fluid and the blood system in the region of the pituitary, may play a role in the regulation of pituitary function and thereby constitute an important neuro-endocrine system.

Constitutive Expression of Glutamic Acid Decarboxylase (GAD) by Striatal Cell Lines Immortalized using the tsA58 Allele of the SV40 Large T Antigen

1996 ◽  
Vol 5 (5) ◽  
pp. 563-575 ◽  
Author(s):  
Magda Giordano ◽  
Hideotoshi Takashima ◽  
Maciej Poltorak ◽  
Herbert M. Geller ◽  
William J. Freed
Keyword(s):  
Glutamic Acid ◽  
Cell Lines ◽  
Glutamic Acid Decarboxylase ◽  
T Antigen ◽  
Acid Decarboxylase ◽  
C Cells ◽  
Large T Antigen ◽  
Type B ◽  
Sv40 Large T Antigen ◽  
Type C

Rodent striatal cells were immortalized using the A58 temperature-sensitive allele of the SV40 large T antigen. Seventy-eight clones and 10 mixed cultures were characterized at the nonpermissive and permissive temperatures. Based on morphology and expression of proteins, cells were classified into three primary types, with types b and c expressing some neuronal characteristics. Type a cells have an epithelial-like morphology with coarse cytoplasmic extensions and occasional fine processes. These cells express vimentin, do not grow well under serum-free conditions and, when confluent, form a uniform monolayer. Type b cells have a polygonal shape and usually extend multiple thin processes. These cells possess large nuclei with multiple nucleoli and do not express vimentin. Type c cells have a fibroblast-like appearance, are unipolar or multipolar, and their soma is smaller than that of type b cells. Type c cells do not express vimentin, and when confluent form a uniform monolayer. Some type b and c clones express NCAM and MAP-2. Several type b and c cell lines were found to consistently express glutamic acid decarboxylase (GAD) immunoreactivity under several tissue culture conditions. Selected cell lines were transplanted into the intact adult rat brain in several locations. Cells survived well for 15 wk and did not form tumors. The proteins expressed in vivo were similar to those expressed in vitro.

Loss of hamster Leydig cells during regression after exposure to a short photoperiod

2018 ◽  
Vol 30 (8) ◽  
pp. 1137 ◽  
Author(s):  
E. Beltrán-Frutos ◽  
V. Seco-Rovira ◽  
J. Martínez-Hernández ◽  
C. Ferrer ◽  
L. M. Pastor
Keyword(s):  
B Cells ◽  
Leydig Cells ◽  
Light And Electron Microscopy ◽  
Type A ◽  
Nuclear Antigen ◽  
Control Group ◽  
C Cells ◽  
Type B ◽  
A Cells ◽  
Type C

The aim of the present study was to evaluate the changes that occur in hamster Leydig cells during regression. Animals were divided into control, mild regression (MR), strong regression (SR) and total regression (TR) groups. Leydig cells were characterised by light and electron microscopy. Terminal deoxyribonucleotidyl transferase-mediated dUTP–digoxigenin nick end-labelling (TUNEL) and proliferating cell nuclear antigen (PCNA) antibodies were used to detect apoptosis and proliferation respectively. Three types of Leydig cells (A, B and C) could be differentiated. Type A cells were small in size compared with Leydig cells from animals exposed to a long photoperiod, which was a result of a decreased cytoplasm and nucleus. Type B cells were even smaller than Type A cells in regression groups. Type C exhibited cytoplasm vacuolisation. The percentage of Type C cells from the control group was much lower than in the MR, SR and TR groups. (P < 0.05). In the SR and TR groups, there was a significant decrease in the percentage of Type B cells compared with the control and MR groups (P < 0.05). The total number of Leydig cells decreased during testicular regression (P < 0.05). The total number of Type A and B cells was significantly lower in the MR, SR and TR groups compared with the control group (P < 0.05). There were no significant differences in the proliferation and apoptosis index in the groups studied. The findings of the present study indicate that there are three types of Leydig cells (A, B and C) in all hamsters studied and that regression causes an increase in the number of Type C cells, so that the reduction in the number Leydig cells during the phases of regression studied must be the result of necrosis and/or necroptosis.

Separation of two bone cell populations from fetal rat calvaria and a study of their responses to parathyroid hormone and calcitonin

1983 ◽  
Vol 99 (3) ◽  
pp. 387-399 ◽  
Author(s):  
I. P. Braidman ◽  
D. C. Anderson ◽  
C. J. P. Jones ◽  
J. B. Weiss
Keyword(s):  
Alkaline Phosphatase ◽  
Parathyroid Hormone ◽  
Acid Phosphatase ◽  
B Cells ◽  
Adenylate Cyclase ◽  
Culture Medium ◽  
Cell Populations ◽  
C Cells ◽  
Type B ◽  
Type C

Bone cells released from perinatal rat calvaria by digestion with clostridial peptidase were separated into two distinct populations (designated types B and C) by equilibrium density centrifugation on a two-step gradient of Percoll. They were extensively characterized by light and electron microscopy and for behaviour in culture, acid and alkaline phosphatase activity, collagen synthesis, collagenase secretion and adenylate cyclase response to parathyroid hormone (PTH) and calcitonin. Type C cells were predominantly large with up to seven nuclei and an unusual cytoplasmic appearance in cytocentrifuge preparations. They did not proliferate in culture and we have established culture conditions which prevented their overgrowth by contaminating proliferative cells. In culture these cells had low alkaline and high acid phosphatase and high aryl sulphatase activity, and synthesized little collagen. In contrast type B cells were mostly smaller and many had irregular cytoplasmic projections. In culture they became polygonal in shape, proliferated rapidly, and reached confluence in 4–5 days. These were low in aryl sulphatase and acid phosphatase, high in alkaline phosphatase activity, and synthesized labelled collagen actively with [3H]proline and ascorbic acid included in the culture medium. The two cell populations were found to differ in culture in two important further respects. First, the type C cells showed an adenylate cyclase response to calcitonin but not to PTH, while the converse was true for type B cells; this was so over at least a 20-fold range of isobutylmethyl xanthine concentration. Secondly, type C cells in culture secreted an active collagenolytic enzyme. Type B cells secreted much lower levels of a predominantly latent collagenase which required activation by mersalyl. Co-culture of type C and type B cells led to a marked reduction in the content of active collagenase in the culture medium.

scholarly journals Steady-state stiffness of utricular hair cells depends on macular location and hair bundle structure

2011 ◽  
Vol 106 (6) ◽  
pp. 2950-2963 ◽  
Author(s):  
Corrie Spoon ◽  
W. J. Moravec ◽  
M. H. Rowe ◽  
J. W. Grant ◽  
E. H. Peterson
Keyword(s):  
Steady State ◽  
Hair Cells ◽  
Head Movement ◽  
Time Course ◽  
Hair Bundle ◽  
Type I ◽  
Response Dynamics ◽  
Functional Interpretation ◽  
Hair Bundles ◽  
Bundle Structure

Spatial and temporal properties of head movement are encoded by vestibular hair cells in the inner ear. One of the most striking features of these receptors is the orderly structural variation in their mechanoreceptive hair bundles, but the functional significance of this diversity is poorly understood. We tested the hypothesis that hair bundle structure is a significant contributor to hair bundle mechanics by comparing structure and steady-state stiffness of 73 hair bundles at varying locations on the utricular macula. Our first major finding is that stiffness of utricular hair bundles varies systematically with macular locus. Stiffness values are highest in the striola, near the line of hair bundle polarity reversal, and decline exponentially toward the medial extrastriola. Striolar bundles are significantly more stiff than those in medial (median: 8.9 μN/m) and lateral (2.0 μN/m) extrastriolae. Within the striola, bundle stiffness is greatest in zone 2 (106.4 μN/m), a band of type II hair cells, and significantly less in zone 3 (30.6 μN/m), which contains the only type I hair cells in the macula. Bathing bundles in media that break interciliary links produced changes in bundle stiffness with predictable time course and magnitude, suggesting that links were intact in our standard media and contributed normally to bundle stiffness during measurements. Our second major finding is that bundle structure is a significant predictor of steady-state stiffness: the heights of kinocilia and the tallest stereocilia are the most important determinants of bundle stiffness. Our results suggest 1) a functional interpretation of bundle height variability in vertebrate vestibular organs, 2) a role for the striola in detecting onset of head movement, and 3) the hypothesis that differences in bundle stiffness contribute to diversity in afferent response dynamics.

Classification of small type B/C follicles as primordial follicles in mature rats

Reproduction ◽  
2000 ◽  
pp. 43-48 ◽  
Author(s):  
S Meredith ◽  
G Dudenhoeffer ◽  
K Jackson
Keyword(s):  
Dna Synthesis ◽  
Granulosa Cells ◽  
Single Layer ◽  
Reliable Indicator ◽  
Type B ◽  
Primordial Follicles ◽  
Type C

In the present study, follicles were classified according to the morphology of their granulosa cells. Type B follicles contained only flattened granulosa cells; type B/C follicles had a mixture of flattened and cuboidal granulosa cells in a single layer, and type C follicles had a single layer of cuboidal granulosa cells. The primary objectives of the study were to determine whether 5-bromo-2-deoxyuridine incorporation into type B/C follicles was a marker for initiation of growth and how long type B/C follicles could remain at the same stage before transformation to type C follicles. Female Holtzman rats received bromo-deoxyuridine for 7 days. After the infusion (day minipumps were removed = day 0), rats were ovariectomized on days 0 (n = 9), 30 (n = 8), 90 (n = 8) and 150 (n = 9). The numbers of type B, B/C and C follicles within one ovary were determined using modified fractionator counting. Analysis over all times demonstrated that there were more (P < 0.0001) type B/C (941 +/- 61 per ovary) than type C (140 +/- 18 per ovary) or type B (159 +/- 19 per ovary) follicles. The numbers of type B and type C follicles did not differ from each other at any time. Only one of 34 rats evaluated had bromo-deoxyuridine-labelled type B follicles. On day 150, 57% of the bromo-deoxyuridine-labelled type B/C follicles remained from day 0. It is concluded that (1) DNA synthesis in granulosa cells of type B/C follicles is not a reliable indicator of impending growth; and (2) type B and type B/C follicles are both components of the pool of primordial follicles.

The tuned displacement response of the hearing organ is generated by the outer hair cells

Neuroscience ◽  
1992 ◽  
Vol 49 (3) ◽  
pp. 607-616 ◽  
Author(s):  
L. Brundin ◽  
Å. Flock ◽  
S.M. Khanna ◽  
M. Ulfendahl
Keyword(s):  
Hair Cells ◽  
Outer Hair Cells ◽  
Displacement Response ◽  
Hearing Organ

scholarly journals Lense-Thirring QPO model testing by QPO phenomena in GX339-4 2010 outburst

2012 ◽  
Vol 8 (S290) ◽  
pp. 211-212
Author(s):  
H. Q. Gao ◽  
J. L. Qu ◽  
Z. Zhang ◽  
J. N. Zhou
Keyword(s):  
Black Hole ◽  
Model Prediction ◽  
Model Testing ◽  
Type B ◽  
Different Types ◽  
Type C

AbstractLense-Thirring QPO model is a promising model to explain QPO phenomena (Ingram et al. (2009)). In this model the QPO results from Lense-Thirring precession of a optical translucent inner hot flow in a truncated disc geometry. Now we check this model with different types QPO (see (Belloni et al. (2011)) for a recent review) of black hole transient (BHT) GX 339-4 2010 outburst and suggest type C QPOs are mainly coincident with this model prediction while type B QPOs are not.

scholarly journals Effects of Clostridium perfringens Beta-Toxin on the Rabbit Small Intestine and Colon

2008 ◽  
Vol 76 (10) ◽  
pp. 4396-4404 ◽  
Author(s):  
Jorge E. Vidal ◽  
Bruce A. McClane ◽  
Juliann Saputo ◽  
Jaquelyn Parker ◽  
Francisco A. Uzal
Keyword(s):  
Small Intestine ◽  
Clostridium Perfringens ◽  
Time Course ◽  
Defense Mechanism ◽  
Intestinal Damage ◽  
Loop Model ◽  
Type B ◽  
Ileal Loop ◽  
Type C ◽  
Beta Toxin

ABSTRACT Clostridium perfringens type B and type C isolates, which produce beta-toxin (CPB), cause fatal diseases originating in the intestines of humans or livestock. Our previous studies demonstrated that CPB is necessary for type C isolate CN3685 to cause bloody necrotic enteritis in a rabbit ileal loop model and also showed that purified CPB, in the presence of trypsin inhibitor (TI), can reproduce type C pathology in rabbit ileal loops. We report here a more complete characterization of the effects of purified CPB in the rabbit small and large intestines. One microgram of purified CPB, in the presence of TI, was found to be sufficient to cause significant accumulation of hemorrhagic luminal fluid in duodenal, jejunal, or ileal loops treated for 6 h with purified CPB, while no damage was observed in corresponding loops receiving CPB (no TI) or TI alone. In contrast to the CPB sensitivity of the small intestine, the colon was not affected by 6 h of treatment with even 90 μg of purified CPB whether or not TI was present. Time course studies showed that purified CPB begins to induce small intestinal damage within 1 h, at which time the duodenum is less damaged than the jejunum or ileum. These observations help to explain why type B and C infections primarily involve the small intestine, establish CPB as a very potent and fast-acting toxin in the small intestines, and confirm a key role for intestinal trypsin as an innate intestinal defense mechanism against CPB-producing C. perfringens isolates.

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