Transducer properties of atrial receptors in the dog after 60 min of increased atrial pressure

1981 ◽  
Vol 59 (8) ◽  
pp. 837-842 ◽  
Author(s):  
C. T. Kappagoda ◽  
M. Padsha
Keyword(s):  
Action Potentials ◽  
Control Period ◽  
Atrial Pressure ◽  
Response Curves ◽  
Experimental Conditions ◽  
Stimulus Response ◽  
Control Value ◽  
Significant Difference ◽  
Initial Control ◽  
Atrial Receptors

This investigation was undertaken to examine the effect of a period of increased atrial pressure lasting 60 min on the ability of atrial receptors to transduce changes in atrial pressure. The experiments were performed on dogs anesthetized with pentobarbitone. Action potentials were recorded from branches of the cervical vagi and the atrial pressure was increased by distending a balloon in the lumen of the left atrium. Twelve receptors were examined in 14 dogs. For each receptor, stimulus–response curves relating the action potentials generated (number per cardiac cycle) to the mean left atrial pressure (centimetres of H2O) were obtained under three experimental conditions: (a) during an initial control period, (b) after 60 min of increased atrial pressure (i.e. 10–12 cm H2O), and (c) 60 min after restoration of the atrial pressure to its control value. It was found that in all 12 units the ability of the receptors to transduce changes in atrial pressure was impaired after 60 min of increased atrial pressure, i.e., the number of action potentials generated by a receptor for the same atrial pressure was smaller than that in the control period. This effect was partially restored in the 12 units 60 min after restoration of the atrial pressures to their respective control values.In four units the stimulus–response curves were repeated 60 min after obtaining the initial control response. It was found that there was no significant difference in each pair of curves. It is concluded that relatively short periods of increased atrial pressure impair transducer properties of the atrial receptors.

Effect of Diazinon PLUS on rapidly adapting receptors in the rabbit

1996 ◽  
Vol 81 (6) ◽  
pp. 2604-2610 ◽  
Author(s):  
Hillary Campbell ◽  
Krishnan Ravi ◽  
Emigdio Bravo ◽  
C. Tissa Kappagoda
Keyword(s):  
Normal Saline ◽  
Action Potentials ◽  
Left Atrial ◽  
Defense Mechanisms ◽  
Control Period ◽  
Atrial Pressure ◽  
Left Atrial Pressure ◽  
Baseline Activity ◽  
Airway Defense ◽  
Control State

Campbell, Hillary, Krishnan Ravi, Emigdio Bravo, and C. Tissa Kappagoda. Effect of Diazinon PLUS on rapidly adapting receptors in the rabbit. J. Appl. Physiol. 81(6): 2604–2610, 1996.—The effects of Diazinon PLUS aerosol on the activities of rapidly adapting receptors (RARs) and slowly adapting receptors (SAR) of the airways were investigated in anesthetized rabbits. The effects on both the baseline activity and the responses to stimulation by increasing mean left atrial pressure were examined. Action potentials were recorded from the left cervical vagus nerve. Aerosols (particle size 3 μm) were generated by a Mini-HEART nebulizer. We observed that an aerosol of Diazinon PLUS (1:10 vol/vol dilution in normal saline) decreased the baseline RAR activity ( n= 10) significantly ( P < 0.05) from 209 ± 77 to 120 ± 40 impulses/min. In the post-Diazinon PLUS control period, the RAR activity recovered partially to 185 ± 75 impulses/min and decreased significantly to 131 ± 52 impulses/min ( P < 0.05) after a second exposure of Diazinon PLUS (undiluted) aerosol. Aerosols of normal saline in the control state did not produce a significant change in the RAR activity. A group of SAR ( n = 8) were examined under similar conditions, and it was found that only the exposure to Diazinon PLUS (undiluted) aerosol decreased the activity significantly ( P < 0.05) from 1,536 ± 206 to 1,367 ± 182 impulses/min. The effect of Diazinon PLUS on the response to increasing mean left atrial pressure was examined in seven RARs. In the control state, RAR activity increased significantly ( P < 0.05) during elevation of mean left atrial pressure. This response was abolished after exposure to Diazinon PLUS. These findings suggest that diazinon may interfere with airway defense mechanisms by reducing the activity of RARs.

Physiological concentrations of ANP exert a dual regulatory influence on renin release in conscious dogs

1992 ◽  
Vol 263 (3) ◽  
pp. R529-R536 ◽  
Author(s):  
H. Ehmke ◽  
P. B. Persson ◽  
A. Just ◽  
B. Nafz ◽  
M. Seyfarth ◽  
...  
Keyword(s):  
Plasma Concentrations ◽  
Renal Perfusion ◽  
Conscious Dogs ◽  
Renin Release ◽  
Complete Suppression ◽  
Control Mechanisms ◽  
Response Curves ◽  
Experimental Conditions ◽  
Stimulus Response ◽  
Extrarenal Renin

The influence of physiological increments in circulating atrial natriuretic peptide (ANP) on renin release was determined in conscious dogs. Renin stimulus-response curves (RSRCs) were obtained by controlled reductions of renal perfusion pressure (RPP) under control conditions and during intrarenal or intravenous ANP infusions. Under all experimental conditions, the RSRCs were characterized by a plateau, a threshold pressure (Pth), and a steep slope below Pth. Intrarenal ANP infusion (0.9 ng.kg-1.min-1), which induced a calculated threefold elevation of renal arterial ANP concentration (but did not change systemic arterial ANP levels), increased the slope of the RSRC by 81% (P less than 0.05) with no effect on Pth. A quantitatively similar effect on the slope of the RSRC (+90%; P less than 0.05) was observed when systemic ANP levels were raised (from 37 +/- 2 to 71 +/- 9 pg/ml; P less than 0.05) by intravenous infusions (3.6 ng.kg-1.min-1). In addition, however, intravenously infused ANP reduced Pth from 91 to 85 mmHg (P less than 0.05), which caused a complete suppression of the renin response to a reduction of RPP down to 85 mmHg. These findings indicate that ANP can inhibit renin release at physiological plasma concentrations by shifting the RSRC to a lower pressure level; this shift is mediated by a modulation of extrarenal renin control mechanisms. The direct effect of ANP on renin release is one of stimulation.

Transient responses to CO2 breathing of human subjects awake and asleep

1963 ◽  
Vol 18 (2) ◽  
pp. 289-294 ◽  
Author(s):  
F. J. D. Fuleihan ◽  
T. Nakada ◽  
J. T. Suero ◽  
E. S. Merrifield ◽  
R. E. Dutton ◽  
...  
Keyword(s):  
Steady State ◽  
Ventilatory Response ◽  
Human Subjects ◽  
Control Period ◽  
Sodium Pentobarbital ◽  
Transient Responses ◽  
Control Value ◽  
Oxygen Breathing ◽  
Significant Difference ◽  
End Tidal

Ventilation and end-tidal Pco2 were studied in six subjects awake and asleep (following the ingestion of 200–300 mg sodium pentobarbital) during oxygen breathing and the administration and withdrawal of 4% CO2 in oxygen. During the control period as well as steady-state CO2 breathing, ventilation was significantly lower in asleep than in awake subjects. There was no significant difference between sleep and wakefulness in end-tidal Pco2 or in the slope of the ventilatory response to 4% CO2. The transient responses of ventilation and end-tidal Pco2 of the group as a whole were similar in sleep and wakefulness. Ventilation changed more slowly than did end-tidal Pco2. End-tidal Pco2 overshot beyond the steady-state CO2 breathing value at the onset of CO2 breathing; and undershot below the control value during recovery. The magnitudes of both the overshoot and undershoot of end-tidal Pco2 were correlated significantly to the slope of the ventilatory response to 4% CO2, in the whole group awake and asleep. Submitted on October 4, 1962

Interaction of left atrial receptors and carotid sinus baroreceptors on heart rate in the dog

1985 ◽  
Vol 248 (5) ◽  
pp. H631-H636 ◽  
Author(s):  
K. K. Teo ◽  
G. C. Man ◽  
C. T. Kappagoda
Keyword(s):  
Heart Rate ◽  
Left Atrial ◽  
Carotid Sinus ◽  
Aortic Pressure ◽  
Response Curves ◽  
Stimulus Response ◽  
Alpha Chloralose ◽  
Atrial Receptors ◽  
Control State ◽  
Stimulation Of

This study was undertaken to determine the influence of 1) the left atrial receptors (LA) on the ability of the carotid sinus baroreceptors (CS) to regulate heart rate and 2) the CS on the reflex increase in heart rate mediated by the LA. The LA were stimulated by stretching the pulmonary vein-atrial junctions in dogs anesthetized with alpha-chloralose. Aortic pressure was controlled, and the pressure in the CS was regulated. Stimulus-response curves were obtained relating heart rate to pressures in the CS, in the control state, and during stimulation of LA (6 dogs). Factorial analysis revealed that LA exerted a significant influence on heart rate (P less than 0.01). Next the CS pressure was set at mid, low, and high levels and the LA stimulated. It was found that the effect on heart rate was greatest at the mid setting (+19.3 +/- 2.9 beats/min) and least at the low setting of the pressure in the CS (+0.9 +/- 0.5, 11 dogs). Sympathetic blockade attenuated significantly the response in the mid setting of the CS pressure and left intact the response at the high setting of the pressure in the CS. It is concluded that there is a significant interaction between these two reflexes.

Voltage-dependent blockade in Na+-dependent action potentials after β1- and H2-receptor stimulation in mammalian ventricular myocardium

1988 ◽  
Vol 66 (10) ◽  
pp. 1291-1296 ◽  
Author(s):  
A. M. Gillis ◽  
M. Kohlhardt
Keyword(s):  
Action Potentials ◽  
Ventricular Myocardium ◽  
Inhibitory Effect ◽  
Receptor Blocker ◽  
Control Value ◽  
Relationship Analysis ◽  
Adrenoceptor Agonist ◽  
Voltage Dependent ◽  
Initial Control ◽  
Β Receptor

In isolated papillary muscles of guinea pigs, the influence of isoproterenol, histamine, theophylline, and phenylephrine on the maximal rate of rise [Formula: see text] of Na+-dependent action potentials and on isometric contractile force was studied under rested state conditions. Isoproterenol (1 × 10−7 mol/L), histamine (2 × 10−5 mol/L), and theophylline (2 × 10−3 mol/L) shifted the voltage dependence of [Formula: see text] into the hyperpolarizing direction and, consequently, led to a voltage-dependent [Formula: see text] blockade. The α-adrenoceptor agonist phenylephrine, on the other hand, proved to be ineffective in depressing [Formula: see text]. The β-receptor blocker pindolol (4 × 10−6 mol/L) or the H2-receptor blocker cimetidine (4 × 10−5 mol/L) abolished the inhibitory effects of isoproterenol and histamine, respectively, and caused [Formula: see text] to return to the initial control value. A concentration–response relationship analysis at −65 mV revealed that isoproterenol exerted only a weak inhibitory effect on [Formula: see text] compared with its positive inotropic action. The IC50 value of the former effect amounted to approximately 5 × 10−6 mol/L, but the EC50 value of the latter effect was 4 × 10−8 mol/L. It is, therefore, concluded that, in physiologically relevant concentrations, β-adrenergic agonists are unlikely to significantly modulate Na+-dependent excitability even in partially depolarized myocardium.

Relevance Predictability in Information Retrieval Systems

1967 ◽  
Vol 06 (02) ◽  
pp. 45-51 ◽  
Author(s):  
A. Kent ◽  
J. Belzer ◽  
M. Kuhfeerst ◽  
E. D. Dym ◽  
D. L. Shirey ◽  
...  
Keyword(s):  
Information Retrieval ◽  
Experimental Conditions ◽  
Treatment Groups ◽  
Retrieval Systems ◽  
Significant Difference ◽  
Information Retrieval Systems ◽  
High Predictability ◽  
Intermediate Response ◽  
Quantitative Indicators ◽  
Level Of Processing

An experiment is described which attempts to derive quantitative indicators regarding the potential relevance predictability of the intermediate stimuli used to represent documents in information retrieval systems. In effect, since the decision to peruse an entire document is often predicated upon the examination of one »level of processing« of the document (e.g., the citation and/or abstract), it became interesting to analyze the properties of what constitutes »relevance«. However, prior to such an analysis, an even more elementary step had to be made, namely, to determine what portions of a document should be examined.An evaluation of the ability of intermediate response products (IRPs), functioning as cues to the information content of full documents, to predict the relevance determination that would be subsequently made on these documents by motivated users of information retrieval systems, was made under controlled experimental conditions. The hypothesis that there might be other intermediate response products (selected extracts from the document, i.e., first paragraph, last paragraph, and the combination of first and last paragraph), that would be as representative of the full document as the traditional IRPs (citation and abstract) was tested systematically. The results showed that:1. there is no significant difference among the several IRP treatment groups on the number of cue evaluations of relevancy which match the subsequent user relevancy decision on the document;2. first and last paragraph combinations have consistently predicted relevancy to a higher degree than the other IRPs;3. abstracts were undistinguished as predictors; and4. the apparent high predictability rating for citations was not substantive.Some of these results are quite different than would be expected from previous work with unmotivated subjects.

OVARIAN ASCORBIC ACID DEPLETION TEST FOR LUTEINIZING HORMONE

1967 ◽  
Vol 56 (4) ◽  
pp. 619-625 ◽  
Author(s):  
Hans Jacob Koed ◽  
Christian Hamburger
Keyword(s):  
Ascorbic Acid ◽  
Luteinizing Hormone ◽  
Dose Response ◽  
Response Curve ◽  
Dose Response Curve ◽  
Human Origin ◽  
Response Curves ◽  
Significant Difference ◽  
The Mean ◽  
Different Levels

ABSTRACT Comparison of the dose-response curves for LH of ovine origin (NIH-LH-S8) and of human origin (IRP-HMG-2) using the OAAD test showed a small, though statistically significant difference, the dose-response curve for LH of human origin being a little flatter. Two standard curves for ovine LH obtained with 14 months' interval, were parallel but at different levels of ovarian ascorbic acid. When the mean ascorbic acid depletions were calculated as percentages of the control levels, the two curves for NIH-LH-S8 were identical. The use of standards of human origin in the OAAD test for LH activity of human preparations is recommended.

STUDIES ON SULFATION FACTOR (SF) ACTIVITY OF HUMAN SERUM

1960 ◽  
Vol XXXV (III) ◽  
pp. 381-396 ◽  
Author(s):  
Sven Almqvist
Keyword(s):  
Human Serum ◽  
Normal Serum ◽  
Treatment Level ◽  
Response Curves ◽  
Normal Children ◽  
Significant Difference ◽  
Human Sera ◽  
Normal Humans ◽  
Pre Treatment ◽  
Dose Levels

ABSTRACT The sulfation factor (SF) activity of human sera has been estimated using a modification of the method of Daughaday et al. (1959). Each assay was statistically evaluated. The method had a mean precision of 0.14 and, used as an assay of GH of human serum, a sensitivity in three pituitary dwarfs of 0.1 to 0.6 μg of HGH/ml of serum. SF activity was found at all ages between 1 month and 75 years. There was a significantly lower mean SF activity below the age of half a year. Three cases of pituitary dwarfism had significantly low SF activities of sera. There was no significant difference between the SF activities of sera from untreated pituitary dwarfs and the sera from normal children below half a year of age. Dose-response curves with large volumes of sera from pituitary dwarfs and small volumes of sera from normal humans had the same slopes. Four mg of HGH prepared according to the method of Li & Papkoff (1956) resulted in a normal serum SF activity in each of the three dwarfs. A significant (P < 0.01) linear relationship was found between the concentration of SF activity of sera from these subjects and the logarithm of the dose of HGH given with dose levels of 1, 2 and 4 mg daily for three days. The decline of serum SF activity to the pre-treatment level following HGH in one dwarf suggested a half life not different from that indicated by others for growth hormone.

Validation of a monetary Taylor Aggression Paradigm: Associations with trait aggression and role of provocation sequence

2020 ◽  
Author(s):  
J Konzok ◽  
L Kreuzpointner ◽  
GI Henze ◽  
L Wagels ◽  
C Kärgel ◽  
...  
Keyword(s):  
Random Sequence ◽  
Reactive Aggression ◽  
Reaction Time Task ◽  
Competitive Reaction ◽  
Experimental Conditions ◽  
Fixed Sequence ◽  
Taylor Aggression Paradigm ◽  
Trait Aggression ◽  
Significant Difference ◽  
In Series

© 2020 Elsevier Inc. The Taylor Aggression Paradigm (TAP) is widely used to measure reactive aggression in laboratory settings. While modified versions (mTAPs) with various stimulus characteristics (shocks, noise, pressure, heat) have already been established, a modified version with monetary stimuli has only been introduced very recently. In this experiment, 209 young healthy participants (104 males, 105 females) completed a mock Competitive Reaction Time Task (CRTT) with a fictional opponent with preprogrammed 40 win and 60 lose trials. In lose trials, participants were provoked by subtracting a low (0–20 euro cents), medium (30–60 cents) or high (70–90 cents) amount of money from their fictitious account. Provocation stimuli were either presented randomly or in a fixed sequence (experimental conditions). In contrast to a random sequence, the fixed sequence was generated by repeating trials from the same provocation category in series of three. Linear mixed models (LMMs) considering aggression trajectories revealed significant effects of provocation (low, medium, high) and trait aggression (K-FAF) on reactive aggression. Men showed significantly higher reactive aggression levels than women. In regard to provocation sequence, we found no significant difference in reactive aggression between the random vs. fixed stimulus sequences. The findings provide new evidence supporting the view that the monetary mTAP is able to induce as well as capture reactive aggression in the laboratory. Additionally, we found no advantage of a fixed sequence as the level of reactive aggression in a given trial appeared to be mainly predicted by the preceding provocation trial.

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