Sodium-dependent receptor current in a new mechanoreceptor preparation

1994 ◽  
Vol 72 (6) ◽  
pp. 3026-3028 ◽  
Author(s):  
M. Juusola ◽  
E. A. Seyfarth ◽  
A. S. French
Keyword(s):  
Mechanical Stimulation ◽  
Action Potentials ◽  
Time Course ◽  
Receptor Potential ◽  
Sodium Ions ◽  
Similar Time ◽  
Sodium Dependent ◽  
Restricted Environment ◽  
Intracellular Microelectrodes ◽  
Stimulation Of

1. Intracellular microelectrodes recorded the receptor potential and receptor current in the neurons of spider slit sense organs during mechanical stimulation of the slits. 2. Mechanical stimulation produced two patterns of action potential discharge, corresponding to the two groups of neurons described previously by electrical stimulation. 3. Tetrodotoxin eliminated the action potentials and revealed a receptor potential with both static and adapting components. Voltage clamp gave an inward receptor current with a similar time course. 4. Replacement of sodium ions in the bath reversibly eliminated the receptor current, indicating that it is carried by sodium ions. However, this effect was comparatively slow, suggesting that the tips of the sensory dendrites lie in a chemically restricted environment.

scholarly journals Receptor Response in Venus's Fly-Trap

1965 ◽  
Vol 49 (1) ◽  
pp. 117-129 ◽  
Author(s):  
Stuart L. Jacobson
Keyword(s):  
Action Potential ◽  
Mechanical Stimulation ◽  
Action Potentials ◽  
Natural Extension ◽  
Receptor Potential ◽  
Mechanical Stimuli ◽  
Dionaea Muscipula ◽  
Receptor Response ◽  
Current Measuring ◽  
Stimulation Of

The insect-trapping movement of the plant Dionaea muscipula (Venus's fly-trap) is mediated by the stimulation of mechanosensory hairs located on the surface of the trap. It is known that stimulation of the hairs is followed by action potentials which are propagated over the surface of the trap. It has been reported that action potentials always precede trap closure. The occurrence of non-propagated receptor potentials is reported here. Receptor potentials always precede the action potentials. The receptor potential appears to couple the mechanical stimulation step to the action potential step of the preying sequence. Receptor potentials elicited by mechanical stimulation of a sensory hair were measured by using the hair as an integral part of the current-measuring path. The tip of the hair was cut off exposing the medullary tissue; this provided a natural extension of the measuring electrode into the receptor region at the base of the hair. A measuring pipette electrode was slipped over the cut tip of the hair. Positive and negative receptor potentials were measured. Evidence is presented which supports the hypothesis that the positive and negative receptor potentials originate from independent sources. An analysis is made of (a) the relation of the parameters of mechanical stimuli to the magnitude of the receptor potential, and (b) the relation of the receptor potentials to the action potential. The hypothesis that the positive receptor potential is the generator of the action potential is consistent with these data.

In vivo study on medullary H(+)-sensitive neurons

1990 ◽  
Vol 69 (4) ◽  
pp. 1408-1412 ◽  
Author(s):  
N. Kogo ◽  
H. Arita
Keyword(s):  
Time Course ◽  
Direct Application ◽  
Ventrolateral Medulla ◽  
Similar Time ◽  
Central Chemoreceptors ◽  
Ph Dependent ◽  
Spontaneously Breathing ◽  
Medullary Neurons ◽  
Stimulation Of

Using the micro pressure ejection technique, we examined responses of medullary neurons with nonphasic discharges (164 units) to direct application of acidified mock cerebrospinal fluid (CSF, pH 6.85-7.05) in decerebrated spontaneously breathing cats. We found 16 H(+)-sensitive cells; they were excited promptly on application of approximately 500 pl of acidified mock CSF in the vicinity of the neuron under investigation, whereas they were unaffected by microejection of the control mock CSF (pH 7.25-7.60). Of the 16 H(+)-sensitive cells, 10 units were further found to be excited by transcapillary stimulation of the central chemoreceptors by using a method of intravertebral arterial injection of CO2-saturated saline. The discharges increased in a similar time course to that of ventilatory augmentation. Distributions of these 10 specific H(+)-sensitive cells were found in the vicinity of nucleus tractus solitarii as well as deep in the ventrolateral medulla. The present results suggest a possibility that pH-dependent central chemoreceptors, if any, would be located in two distinct medullary regions described in this study.

Effect of Several Cations on Transmembrane Potentials of Cardiac Muscle

1956 ◽  
Vol 186 (2) ◽  
pp. 317-324 ◽  
Author(s):  
Brian F. Hoffman ◽  
E. E. Suckling
Keyword(s):  
Action Potential ◽  
Cardiac Muscle ◽  
Action Potentials ◽  
Time Course ◽  
Pacemaker Activity ◽  
Transmembrane Potentials ◽  
High K ◽  
Intracellular Microelectrodes ◽  
Simultaneous Decrease ◽  
Low K

The effects of changes in the extracellular concentrations of Ca, K and Mg on the transmembrane resting and action potentials of single fibers of the auricle, ventricle and specialized conducting system of the dog heart have been studied by means of intracellular microelectrodes. With respect to Ca, the three tissues exhibit quite different sensitivities. Changes in concentration of this ion alter the time course of the action potential recorded from auricle and ventricle but have little effect on the action potential configuration of the Purkinje fiber. In the latter tissue, on the other hand, pacemaker activity is most strongly enhanced by Ca depletion and excitability is lost at Ca concentrations permitting normal propagation in papillary muscle. The effect of K on the resting transmembrane potential is dependent on the simultaneous Ca concentration. The interrelationship is such that the depolarizing effect of high K is decreased by elevated Ca and the depolarization produced by low K is diminished by low levels of Ca. Changes in the concentration of Mg have little effect on the transmembrane potentials of cardiac muscle unless the level of Ca is low. Under this condition a simultaneous decrease in Mg gives rise to a marked prolongation of the action potential duration of both auricle and ventricle. Some evidence for the basic similarity of the processes underlying repolarization in these three tissues is presented and it is thought the normally encountered differences in their action potentials may be related to the sensitivity of each tissue to extracellular Ca.

scholarly journals Anatomical and functional characterization of a duodeno-pancreatic neural reflex that can induce acute pancreatitis

2013 ◽  
Vol 304 (5) ◽  
pp. G490-G500 ◽  
Author(s):  
Cuiping Li ◽  
Yaohui Zhu ◽  
Mohan Shenoy ◽  
Reetesh Pai ◽  
Liansheng Liu ◽  
...  
Keyword(s):  
Acute Pancreatitis ◽  
Cross Talk ◽  
Mechanical Stimulation ◽  
Transient Receptor Potential ◽  
Functional Characterization ◽  
Receptor Potential ◽  
Splanchnic Nerve ◽  
Mustard Oil ◽  
Myeloperoxidase Activity ◽  
Stimulation Of

Neural cross talk between visceral organs may play a role in mediating inflammation and pain remote from the site of the insult. We hypothesized such a cross talk exists between the duodenum and pancreas, and further it induces pancreatitis in response to intraduodenal toxins. A dichotomous spinal innervation serving both the duodenum and pancreas was examined, and splanchnic nerve responses to mechanical stimulation of these organs were detected. This pathway was then excited on the duodenal side by exposure to ethanol followed by luminal mustard oil to activate transient receptor potential subfamily A, member 1 (TRPA1). Ninety minutes later, pancreatic inflammation was examined. Ablation of duodenal afferents by resiniferatoxin (RTX) or blocking TRPA1 by Chembridge (CHEM)-5861528 was used to further investigate the duodeno-pancreatic neural reflex via TRPA1. ∼40% of dorsal root ganglia (DRG) from the spinal cord originated from both duodenum and pancreas via dichotomous peripheral branches; ∼50% splanchnic nerve single units responded to mechanical stimulation of both organs. Ethanol sensitized TRPA1 currents in cultured DRG neurons. Pancreatic edema and myeloperoxidase activity significantly increased after intraduodenal ethanol followed by mustard oil (but not capsaicin) but significantly decreased after ablation of duodenal afferents by using RTX or blocking TRPA1 by CHEM-5861528. We found the existence of a neural cross talk between the duodenum and pancreas that can promote acute pancreatitis in response to intraduodenal chemicals. It also proves a previously unexamined mechanism by which alcohol can induce pancreatitis, which is novel both in terms of the site (duodenum), process (neurogenic), and receptor (TRPA1).

STIMULATORY EFFECT OF PROLACTIN ON INCORPORATION OF [3H]THYMIDINE INTO THE URINARY BLADDER OF THE FLOUNDER (KAREIUS BICOLORATUS)

1973 ◽  
Vol 56 (3) ◽  
pp. 591-597 ◽  
Author(s):  
TETSUYA HIRANO ◽  
SEIICHI HAYASHI ◽  
SEIITIRO UTIDA
Keyword(s):  
Urinary Bladder ◽  
Time Course ◽  
Thymidine Incorporation ◽  
Leucine Incorporation ◽  
Physiological Changes ◽  
Sodium Ions ◽  
Cell Turnover ◽  
Specific Stimulation ◽  
Kareius Bicoloratus ◽  
Stimulation Of

SUMMARY Administration of prolactin for 3 or 5 days to the seawater-acclimatized flounder, Kareius bicoloratus, resulted in a significant increase in the incorporation of [3H]thymidine into the DNA fraction of the urinary bladder. When isolated bladders were incubated in isotonic Ringer solutions on both mucosal and serosal sides, net movement of water from mucosa to serosa decreased significantly after 3 or 5 daily injections of prolactin, whereas net absorption of sodium ions increased concomitantly; the time-course closely corresponded to that of thymidine incorporation. Tendency toward an increase in [14C]uridine and [3H]leucine incorporation was also observed in the urinary bladder after 5 daily injections of prolactin. However, incorporation of thymidine, uridine and leucine into the intestine was not affected at all by prolactin treatment for 5 days. All three isotopically labelled compounds were incorporated similarly into the urinary bladder and the intestine of control seawater flounders. Cell turnover in the urinary bladder is apparently as rapid as that in the intestine; specific stimulation of cell proliferation by prolactin may be an important factor in the induction of physiological changes in the bladder of the flounder.

Intensity and frequency characteristics of pacinian corpuscles. III. Effects of tetrodotoxin on transduction process

1984 ◽  
Vol 51 (4) ◽  
pp. 831-839 ◽  
Author(s):  
S. J. Bolanowski
Keyword(s):  
Vibration Frequency ◽  
Action Potentials ◽  
Time Course ◽  
Receptor Potential ◽  
Frequency Characteristics ◽  
Cycle Period ◽  
Driving Frequency ◽  
Pacinian Corpuscles ◽  
Percentage Decrease ◽  
High Stimulus

This is the third in a series of three papers dealing with intensity and frequency characteristics obtained on pacinian corpuscles isolated from the cat mesentery (8, 9). The experimental results show that tetrodotoxin (TTX) affects not only regenerative action potentials but also the measured receptor (generator) potentials. Extracellularly recorded receptor and action potentials were simultaneously recorded in response to sinusoidal displacement stimuli. Receptor potentials measured in this manner responded with a time course similar to the driving frequency. Since the duration of the action potentials is long relative to the cycle period at high stimulus frequencies, the underlying receptor potentials can become obscured. To prevent this, TTX was applied through superfusion at a concentration of 6.0 microM. After about 30 min, the neural spikes were fully eliminated but the receptor potentials were also decreased in amplitude. Intensity characteristics relating receptor-potential amplitudes to probe displacement amplitudes showed that the percentage decrease in amplitude due to the application of TTX was constant regardless of stimulus intensity. Frequency characteristics relating probe displacement amplitudes to vibration frequency for a constant-response criterion showed an increase in the displacement amplitude required for the criterion response, across frequency, when TTX was applied. On average, the increase was a power function of vibration frequency.(ABSTRACT TRUNCATED AT 250 WORDS)

Gastric vagal-evoked and greater splanchnic-evoked unitary responses in the hypothalamus

1993 ◽  
Vol 264 (6) ◽  
pp. G1133-G1141 ◽  
Author(s):  
W. D. Barber ◽  
C. S. Yuan
Keyword(s):  
Action Potentials ◽  
Time Course ◽  
Splanchnic Nerve ◽  
Nerve Fibers ◽  
Hypothalamic Neurons ◽  
Proximal Stomach ◽  
Neuronal Interactions ◽  
Greater Splanchnic Nerve ◽  
Two Peaks ◽  
Stimulation Of

Gastric vagal and greater splanchnic nerve fibers were electrically stimulated to localize and characterize neuronal interactions in the hypothalamus of anesthetized cats. Extracellular recordings from 635 hypothalamic units were identified that responded to electrical stimulation of the left greater splanchnic nerve or gastric vagal fibers serving the proximal stomach. A total of 504 hypothalamic units in this group received input from both gastric vagal and greater splanchnic nerves. The gastric vagal-evoked hypothalamic (GVeH) and greater splanchnic-evoked hypothalamic (SeH) responses were widely distributed in the medial, paraventricular, and dorsomedial nuclei and lateral hypothalamus. The conduction velocity of the SeH response was significantly greater than the GVeH response. The latency of the SeH response showed two peaks [58 +/- 15.7 (SD) ms and 136 +/- 18.3 (SD) ms] indicating that the splanchnic input terminated on two different groups or populations of hypothalamic neurons. It also suggested that different pathways or fiber diameters in the pathway may be involved in the transmission of splanchnic input to the hypothalamus. The majority of the GVeH and SeH unitary responses were multiple spikes or short trains of action potentials. Excitatory and inhibitory responses were observed in tonically active hypothalamic units that responded to gastric vagal or greater splanchnic input. The duration of decreased excitability to gastric vagal or greater splanchnic input was significantly greater than the period of increased excitability. The condition-test paradigm was used to determine the time course of convergent gastric vagal-greater splanchnic input on single hypothalamic neurons.(ABSTRACT TRUNCATED AT 250 WORDS)

The Langerhans receptor of Oikopleura (Tunicata: Larvacea)

1979 ◽  
Vol 59 (1) ◽  
pp. 69-75 ◽  
Author(s):  
Q. Bone ◽  
K. P. Ryan
Keyword(s):  
Epithelial Cells ◽  
Gap Junctions ◽  
Mechanical Stimulation ◽  
Action Potentials ◽  
Electrical Synapses ◽  
Locomotor Rhythm ◽  
Receptor Cells ◽  
Stimulation Of

The bristle-bearing receptors on either side of the trunk in Oikopleura are connected to the caudal ganglion by the axons of central cells which form electrical synapses (gap junctions) at the bases of the receptor cells. The same axons also form similar synapses with epithelial cells adjacent to the receptors. Direct mechanical stimulation of the receptor processes evokes changes in the locomotor rhythm of the same kind as evoked by action potentials propagated in the epithelial cells. This remarkable arrangement is suggested to be a consequence of the reduced numbers of cells in larvaceans.

Calcium transients in intact rat skeletal muscle fibers in agarose gel

1995 ◽  
Vol 269 (1) ◽  
pp. C28-C34 ◽  
Author(s):  
S. L. Carroll ◽  
M. G. Klein ◽  
M. F. Schneider
Keyword(s):  
Action Potentials ◽  
Time Course ◽  
Calcium Transients ◽  
Agarose Gel ◽  
Similar Time ◽  
Single Action ◽  
Fura 2 ◽  
Calcium Indicator ◽  
Flexor Digitorum Brevis ◽  
Time Courses

Intact single fibers enzymatically dissociated from rat flexor digitorum brevis muscle were suspended in 0.5% low-melting-temperature agarose gel to minimize fiber movement during action potentials or trains of action potentials. Resting Ca2+ concentration ([Ca2+]) and changes in [Ca2+] were monitored using the fluorescent calcium indicator fura 2. The time course and waveform of [Ca2+] transients during an action potential or trains of action potentials in fibers in agarose were calculated using kinetic parameters previously determined to correct for the calcium-fura 2 kinetic delay. Half times of the calculated calcium transients for single action potentials were 30-fold briefer than the original fura 2 signals. To confirm the time course and waveform of the calculated calcium transients, changes in [Ca2+] were monitored using the more rapidly equilibrating calcium indicator mag-fura 2. [Ca2+] transients for fibers containing fura 2 had very similar time courses and waveforms as mag-fura 2 signals from other fibers, indicating that the corrections for the calcium-fura 2 kinetic delay were accurate. The advantages of the agarose gel suspension are discussed.

scholarly journals Structure and function of the nervous system in nectophores of the siphonophore Nanomia bijuga

2020 ◽  
Vol 223 (24) ◽  
pp. jeb233494
Author(s):  
Tigran P. Norekian ◽  
Robert W. Meech
Keyword(s):  
Action Potentials ◽  
Time Course ◽  
Lower Surface ◽  
Muscle Fibres ◽  
Muscle System ◽  
Slow Potentials ◽  
Nerve Tracts ◽  
System Part ◽  
And Function ◽  
Stimulation Of

ABSTRACTAlthough the bell-shaped nectophores of the siphonophore Nanomia bijuga are clearly specialized for locomotion, their complex neuroanatomy described here testifies to multiple subsidiary functions. These include secretion, by the extensively innervated ‘flask cells' located around the bell margin, and protection, by the numerous nematocytes that line the nectophore's exposed ridges. The main nerve complex consists of a nerve ring at the base of the bell, an adjacent column-shaped matrix plus two associated nerve projections. At the top of the nectophore the upper nerve tract appears to have a sensory role; on the lower surface a second nerve tract provides a motor input connecting the nectophore with the rest of the colony via a cluster of nerve cells at the stem. N. bijuga is capable of both forward and backward jet-propelled swimming. During backwards swimming the water jet is redirected by the contraction of the Claus' muscle system, part of the muscular velum that fringes the bell aperture. Contractions can be elicited by electrical stimulation of the nectophore surface, even when both upper and lower nerve tracts have been destroyed. Epithelial impulses elicited there, generate slow potentials and action potentials in the velum musculature. Slow potentials arise at different sites around the bell margin and give rise to action potentials in contracting Claus’ muscle fibres. A synaptic rather than an electrotonic model more readily accounts for the time course of the slow potentials. During backward swimming, isometrically contracting muscle fibres in the endoderm provide the Claus' fibres with an immobile base.

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