Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “REST”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 937 records · Page 52Linked to original sources
PubMedDate not supplied

Regional cerebral blood flow SPECT study, at rest and during Wisconsin Card Sorting Test (WCST) performance, in schizophrenia naive patients or treated with atypical neuroleptics.

INTRODUCTION: To corroborate the hypothesis of hypofrontality in schizophrenia and to study the relationship between positive/negative symptoms (measured by the positive and negative syndrome scale [PANSS]) and regional cortical blood flow (rCBF), both at rest and during the Wisconsin Card Sorting Test (WCST) performance (activation). METHODS: We compared a control group (n = 18) to a group of patients with schizophrenia (n = 21) in terms of rCBF, measured by single photon emission computed tomography (SPECT). RESULTS: We found significantly higher left-frontal- CBF (during the WCST performance and at rest) and right-frontal-CBF (only at rest) in control subjects. Only the control group showed a right-frontal-CBF increase during activation. Only the patients group showed a significant right-occipital-CBF increase during the activation. We observed a positive significant correlation between the PANSS-P score and the left- frontal index at rest. Some negative symptoms such as difficulty in abstract thinking (N5) and lack of spontaneity and flow of conversation (N6) are associated to low frontal blood flow at rest. Affective blunting (N1) is associated to low left-frontal blood flow during activation. CONCLUSIONS: Our data support the hypothesis of hypofrontality, at rest and during activation, which means the incapacity of schizophrenic patients to increase the frontal CBF while performing the WCST (activation). Schizophrenia positive symptoms are associated to high left-frontal blood flow.

Adult↗
PubMed1991

Coupled in vivo activity of creatine phosphokinase and the membrane-bound (Na+,K+)-ATPase in the resting and stimulated electric organ of the electric fish Narcine brasiliensis.

Physiological control of the plasma membrane sodium pump, (Na+,K+)-ATPase, is essential for proper function of eukaryotic cells. In the electric organ of the elasmobranch Narcine brasiliensis, the normal demands placed upon the pump during the process of generation of electrical currents call for large and rapid changes in activity of this enzyme, making this a good model for the study of its cellular regulation. 31P NMR spectroscopic techniques were used to study metabolic regulation of membrane pump function in resting and stimulated electric organ and in skeletal muscle of the live, intact N. brasiliensis. Because the ATP synthetic abilities of the electric organ by glycolysis or oxidative phosphorylation are extremely limited, depletion of phosphocreatinine (PCr) could be used to determine the activity of the (Na+,K+)-ATPase after the electric organ was stimulated to discharge, and to measure the net flux from PCr to ATP through the creatine phosphokinase (CPK) reaction in the electric organ. Saturation transfer, an NMR technique which measures exchange rates, was applied to determine the unidirectional flux in the forward direction through the same reaction in the electric organ and in skeletal muscle as a control. The pseudo first-order rate constant kf for the CPK reaction at 24 degrees C in resting electric organ was 0.000 +/- 0.002 s-1 (n = 10) and in skeletal muscle was 0.08 +/- 0.03 s-1 (n = 3). The results demonstrate that in resting electric organ, which is well supplied with CPK, there was no measurable flux through this reaction, although CPK when extracted is highly active. Measured and calculated levels of all substrates for the creatine kinase reaction in the electric organ are similar to those in unstimulated skeletal muscle, where the creatine phosphokinase reaction rates are high in vivo. In contrast to the resting electric organ, during stimulation of the electric organ the measured net rate constant was greater than 0.08 s-1. In addition, as shown by lack of PCr depletion, there was virtually no net turnover of ATP in the resting organ compared to the stimulated organ. The marked difference in the (Na+,K+)-ATPase activity in the resting and activated electric organ confirmed earlier results (Blum, H., Nioka, S., and Johnson, R. G., Jr. (1990) Proc. Natl. Acad. Sci. U. S. A. 87, 1247-1251). Together, these results suggest that there is a novel method of coordinate regulation of cellular enzymes of great sensitivity and rapidity.

Adenosine Triphosphate↗
PubMed2006

[Adjuvant chemotherapy with TS-1 for head and neck cancer--side effect of two-week application followed by one-week rest regimen].

Multimodality therapy incorporated with radiotherapy, surgery and chemotherapy are used in the treatment of head and neck cancer in order to improve the local control and survival rate. TS-1, a newly developed oral antitumor agent which could achieve the same therapeutic concentration as that of 5-FU under continuous and intravenous treatment, has been used as adjuvant therapy for carcinomas in recent years. We presented our experience applying a new regimen of TS-1 and its side effects. TS-1 has been applied for head and neck carcinomas since 2001. The oral application of TS-1 has been used in 32 cases of head and neck cancer in our department since 2003, and the agent has been applied in 22 of 32 cases as adjuvant therapy. The primary sites of malignancy included hypopharyngx (7 cases), larynx (6 cases), maxillary sinus (2 cases), oropharynx (2 cases), oral cavity (4 cases), submandibular gland (1 case) and one case in which the primary site was unknown. A regimen of four-week application followed by two-week rest had been used in 6 cases in the first part of this trial. However, a high frequency of blood toxicity was found from the third week, requiring alteration of the protocol. Thus, a new regimen of two-week application followed by one week rest was thereafter used in the other 16 cases. Blood toxicity was found in 66.7% of those cases receiving a four-week application followed by two-week rest regimen. In the 16 cases receiving the two-week application followed by one-week rest regimen, only one case showed grade 2 leucopenia while continuous application for more than eight weeks was possible in 9 cases. Mild macrocytic anemia was found in some of these cases, however none of which required any necessary interruption of the treatment. Side effects other than blood toxicity, such as edema or pigmentation of lower limbs, erythema of skin and diarrhea, were found in the other cases, requiring suspension of the treatment. But the subsequent application was possible after a break or decreasing the dosage. We concluded that the new regimen of two-week application followed by one-week rest is less likely to be interrupted by the side effects and is safer to be used outpatiently, compared with the four-week application followed by two-week rest.

Administration, Oral↗
PubMed2006

[The relationship between resting heart rate and single nucleotide polymorphism at 3 sites of nitric oxide synthase gene in the Chinese Han nationality population].

OBJECTIVE: To study the relationship between resting heart rate and single nucleotide polymorphisms (SNP) at 3 sites of nitric oxide synthase (NOS) gene including NOS3 -922A/G, NOS3 894G/T and NOS2 -1173C/T SNPs. METHODS: Genomic DNA was gained from 211 Chinese Han nationality population. The SNPs of NOS3 -922A/G, NOS3 894G/T and NOS2 -1173C/T were genotyped by allele-specific primer-polymerase chain reaction (ASP-PCR) technique. RESULTS: The distribution frequencies of GG, GT and TT genotypes of NOS3 894G/T and AA, AG and GG genotypes of NOS3 -922A/G and CC, CT and TT genotypes of NOS2 -1173C/T were consistent with Hardy-Weinberg equilibrium (P> 0.05). The resting heart rate of Chinese Han nationality population with AA genotypes was higher than that with GG genotype of NOS3 -922A/G (P< 0.01). The resting heart rate of the sub-population with GG genotype was higher than that with TT genotype of NOS3 894G/T (P< 0.05). There were no difference among the resting heart rates of the sub-populations with the allele genotypes of NOS2 -1173C/T. CONCLUSION: The resting heart rate of Chinese Han nationality population with mutated genotype GG of NOS3 -922A/G and with mutated genotype TT of NOS3 894G/T were lower than those with wild genotype of NOS3 -922A/G and NOS3 894G/T. The finding suggests that resting heart rate is associated with SNP of NOS3 -922A/G and NOS3 894G/T.

Adult↗
PubMed1991

Post-rest contractions of amphibian cardiac muscle.

Post-rest potentiated contractions have been reported to be more dependent on Ca2+ stored in intracellular sites than on transmembrane Ca2+ influx. The phenomenon was examined using toad ventricular strips contracting isometrically and superfused with Ringer solution. Toad ventricular strips did not present post-rest potentiation, a fact that may be explained by the reduced volume of the sarcoplasmic reticulum in the amphibian myocardium. Potentiated post-rest contractions were obtained after calcium influx blockade with 10 microM verapamil or 2 mM Mn2+ and the slow reduction of extracellular Ca2+ concentration obtained by slowly exchanging the bath fluid was accompanied by a progressive decrease of both steady-state and post-rest contractions. These data confirm the observations made on other species regarding the post-rest potentiation phenomenon and support the suggestion of the dependence of post-rest potentiation on activator calcium liberated from intracellular stores.

Animals↗
PubMed1991

Differential detachment from resting hosts of replete larval and nymphal Ixodes ticks.

To determine whether replete subadult Ixodes ticks detach more frequently from resting than from active hosts, diverse rodents and lizards were caged in an apparatus designed to record the ticks' sites of detachment relative to the resting site of the host. Replete larval Ixodes ricinus and Ixodes dammini accumulated mainly beneath the resting places of the mice (Apodemus agrarius and Peromyscus leucopus) most frequently parasitized in nature. Although nymphal I. ricinus similarly detached where these mice rested, nymphal I. dammini detached more randomly. When lizards were used as hosts, both subadult stages of I. ricinus tended to detach away from their main resting sites; these ticks detached from squirrels more randomly. Detachment ratios for other rodent hosts, that are abundantly infested by the larvae of these ticks in nature (Apodemus flavicollis and Clethrionomys glareolus), could not be derived because nymphs generally failed to attach. Our observations are consistent with reports that both subadult stages of I. dammini, but not the adult, feed on the same kind of nest-dwelling hosts and that the host range of I. ricinus is less focused. Detachment of mouse-feeding larvae from resting mice promotes subsequent nymphal attachment to conspecific hosts, and the absence of such behavior among nymphs facilitates access of the resulting adults to deer.

Animals↗
PubMed1990

The "REST" program: a new treatment system for the oppositional defiant adolescent.

This study compared the REST (Real Economy System for Teens) program with traditional talk therapy in the treatment of oppositional defiant adolescents. The REST program uses rules for five target behaviors: room care, personal hygiene, completion of chores, abusiveness, and safety violations. Objective measures and subjective parental ratings were taken. Twenty-five adolescents were assigned to each therapy group. In the REST program the adolescent was provided with only food and shelter. The adolescent had to earn money through the REST allowance program to pay for everything else. Earning the allowance was made contingent upon compliance with all rules for the five target behaviors. The results showed significantly greater improvement on all target behaviors for the REST program than for traditional therapy. In addition, parents of adolescents in the REST group reported that their adolescents seemed happier, more relaxed, and closer to them.

Adolescent↗
PubMed1990

Rest and exercise hemodynamics of 20 to 23 mm allograft, Medtronic Intact (porcine), and St. Jude Medical valves in the aortic position.

Doppler echocardiography was used to measure gradients and valve areas at rest and after supine bicycle exercise in 35 patients with valve replacements 20 to 23 mm in size. Thirteen patients with a St. Jude Medical valve (St. Jude Medical, Inc., St. Paul, Minn.) were matched to 13 patients with an allograft valve, and seven patients with a Medtronic Intact (porcine) valve (Medtronic, Inc., Minneapolis, Minn.) to seven patients with an allograft valve. Patients were matched for age, sex, valve size, body surface area, and left ventricular systolic function. There was no statistically significant difference between the matched groups for body surface areas, resting cardiac output, exercise heart rate, or workload achieved. Mean pressure gradient was higher for St. Jude Medical than for allograft groups, both at rest (11.8 +/- 6.67 mm Hg for St. Jude Medical versus 6.67 +/- 2.98 mm Hg for allografts) and after exercise (16.4 +/- 8.47 mm Hg versus 9.7 +/- 3.94 mm Hg), but the differences were of borderline significance (p = 0.016 and 0.027, respectively). Valve area at rest was similar for both devices (1.4 +/- 0.45 cm2 for St. Jude Medical versus 1.8 +/- 0.56 cm2 for allograft; p greater than 0.1). There were highly significant differences between patients with Intact and those with allograft valves for resting mean pressure gradient (19.3 +/- 4.23 mm Hg for Intact versus 5.9 +/- 3.68 mm Hg for allograft; p less than 0.001) and for exercise mean pressure gradient (27.8 +/- 8.63 mm Hg versus 8.1 +/- 8.43 mm Hg; p less than 0.001). The differences between the valve areas at rest also were significant (1.1 +/- 0.12 cm2 versus 2.2 +/- 0.62 cm2; p less than 0.01). It is concluded that when a tissue valve is indicated in patients with a small aortic root, the freehand allograft aortic valve is an ideal device from the hemodynamic perspective and is superior to the Intact valve. It is also probably superior in this respect to the St. Jude Medical valve, although the analysis may be biased slightly in favor of the allograft valve.

Aged↗
PubMed1990

Uterine resting tonus and maternal hypertension during late pregnancy--existence of intrauterine capacity.

The uterine resting tonus was measured with an open-end catheter beginning from the 24th gestational week through the onset of labor in order to investigate changes in the intrauterine environment from the physical aspect. The measurements were performed in 183 primiparas for a total of 272 times and 102 multiparas for a total of 120 times. The uterine resting tonus was almost constant from the 2nd trimester through the 3rd trimester, but it tended to increase gradually beginning 2-3 weeks prior to the onset of delivery. This tendency was more pronounced in primiparas, and their mean tonus was about 5mmHg higher than that of multiparas throughout the pregnancy. In 55 subjects in whom both the resting tonus and blood pressure were simultaneously measured at least twice during pregnancy, the mean maternal blood pressure increased as the resting tonus increased. The above findings revealed a positive correlation between the resting tonus and the maternal blood pressure and suggested the presence of a critical point in terms of the intrauterine capacity, which derives from the properties of the uterine muscle and the intrauterine contents, consisting mainly of the fetus. The increase in the resting tonus is surmised to be related to this critical point.

Adult↗
PubMed1986

Supernatant from a cloned helper T cell stimulates most small resting B cells to undergo increased I-A expression, blastogenesis, and progression through cell cycle.

Helper T cell clone 52.3 supernatant (52.3 SN) was previously shown to be able to stimulate gradient-purified murine resting B cells in the absence of any additional stimulus. However, the proportion of cells that were accounting for the thymidine uptake and the Ig production was unknown. In this paper, we have studied induced changes that can be measured at the single cell level, and have thus determined the frequency of resting B cells that respond to 52.3 SN. Results indicate that 52.3 SN induces an increased I-A expression and a cell size enlargement on virtually all resting B cells. A significant proportion (30%) of these cells later becomes large blasts. Acridine orange staining revealed that in the presence of 52.3 SN a large fraction of the resting B cells undergoes the G0 to G1 transition. Furthermore, 52.3 SN is able to induce at least 20% of the cells to continue through the cell cycle into S phase as indicated by propidium iodide staining of DNA. Finally, a fraction of the 52.3 SN-stimulated cells differentiate to Ig-producing cells. Our present results suggest that resting B cells express functional receptors for some lymphokines and that these lymphokines can act in the absence of membrane Ig occupancy. Our findings further support the existence of a B cell-activating factor acting in a MHC-unrestricted manner and responsible for the entry of resting B cells into cell cycle. The relationship between this factor and other lymphokines is discussed.

Acridine Orange↗
PubMed1989

Regulation of resting and cycling human B lymphocytes via surface IgM and the accessory molecules interleukin-4, CD23 and CD40.

Experiments were designed in order to compare directly the ability of a new and potent monoclonal anti-mu chain antibody to initiate or maintain stimulation in resting and cycling B lymphocytes, respectively. Resting B cells could be stimulated by soluble anti-mu only in the presence of additional signals; these could be supplied by a high dose of phorbol ester or a combination of interleukin-4 (IL-4) and the CD40 antibody, G28-5. Immobilization of anti-mu not only increased the magnitude of the resting B-cell response but also diminished the co-factor requirements. The 'background' stimulation obtained when using a high concentration of immobilized anti-mu was unexpectedly reduced in the presence of IL-4 alone. The duration, but not the magnitude, of the IL-4 signal required for promoting optimal responses varied with the co-stimulation applied. Importantly, the threshold concentrations of soluble anti-mu needed to trigger the resting B cells were reduced upon the addition of each co-stimulant. With actively cycling B cells, both soluble and immobilized anti-mu were now capable of sustaining stimulation which could be prolonged on the addition of IL-4 and/or G28-5. In both resting and cycling populations, a strong correlation was noted between the magnitude of stimulation elicited when IL-4 was present and the release of the soluble CD23 molecule. Moreover, IL-4-promoted, but not other, stimulations could be augmented up to 10-fold by the inclusion of the CD23 antibody MHM6. Both the resting and cycling B-cell populations were found to secrete IgM in direct response to IL-4 and G28-5; this factor-driven production of IgM was differentially modulated by soluble and immobilized anti-mu in the two populations.

Antibodies, Monoclonal↗
PubMed1989

[Variations of clinical rest position in complete denture-wearing subjects].

With a view to proposing concrete grounds for the measurement of the rest vertical dimension on the face in the establishment of the vertical dimension of occlusion for edentulous patients, 20 complete denture-wearing subjects were made to take a clinical rest position by 4 different denture-wearing patterns, i.e. setting both dentures (UL), setting maxillary denture only (U), setting mandibular denture only (L) and completely edentulously (O), and were measured for the distance between 2 points on the face by slide calipers masking the reading part. The data were statistically analyzed and the following results were obtained. 1) Rest vertical dimension was largest for L, and significant differences were noted between UL, O, U and L, but not between UL and O, between UL and U and between O and U. 2) No significant difference in rest vertical dimension was noted between subjects of not more than 65 years and those of not less than 65 years. 3) No significant difference in rest vertical dimension was noted between the group of subjects of not more than 6 edentulous years and that of subjects of not less than 6 edentulous years. 4) The above results give suggestions to the measurement and evaluation of the vertical dimension between 2 points on the face when jaws are in the vertical relationship with the clinical rest position, in the establishment of the vertical dimension of occlusion.

Age Factors↗
PubMed1986

[Comparative studies of Fc receptors for IgG on resting and activated mouse T lymphocytes using different methods].

Fc-receptors for IgG (Fc gamma R) on resting (i.e. freshly prepared) and mitogen (Con A) or alloantigen-activated mouse spleen T cells were compared using binding of different markers such as 125J-labelled immune complexes, 125J-labelled anti Fc gamma R monoclonal antibody, FITC-labelled aggr. IgG and sheep erythrocytes covered with specific antibody (EA rosetting). C3b receptors were detected by rosetting with sheep erythrocytes covered with antibody and complement (EAC rosetting). The electrophoretic mobility of the cells without or after binding of aggr. IgG was also tested. A number of differences between resting and activated T cells were found: After activation of T cells by mitogen or alloantigen, a proportion of Fc gamma R-positive cells increased two to four times. Fc gamma R number per Fc gamma R-positive cell seemed to be higher on activated then on resting cells. Fc gamma R-positive resting cells did not shed their Fc gamma R upon incubation at 4 degrees C followed by incubation at 37 degrees C, but Fc gamma R-positive activated cells shed a remarkable proportion of their Fc gamma R on the same conditions. Binding of aggr. IgG caused a decrease of electrophoretic mobility of activated but not resting cells. Fc gamma R-positive resting cells were also C3b receptor-positive, whereas Fc gamma R-positive activated cells had no detectable C3b receptors.

Animals↗
PubMedDate not supplied

Effects of severity of mitral stenosis on left and right ventricular function at rest and during exercise.

Few studies have assessed the effect of severity of mitral stenosis (MS) on ventricular function. Using equilibrium radionuclide ventriculography to measure ejection fraction and volume changes, 63 patients were studied during supine, symptom-limited exercise. To more carefully assess the 12 patients with MS and impaired left ventricular function, 2 groups of patients were formed. Group I (n = 51) had a normal (less than 50%) resting left ventricular (LV) ejection fraction (EF) and group II (n = 12) had an abnormally low (less than 50%) resting LVEF. Both groups were divided into mild (greater than 1.4 cm2), moderate (1.1-1.4 cm2) and severe (less than 1.0 cm2) MS. There were no differences in mean rest or exercise LVEF for group I. Exercise LVEF increased significantly (p less than 0.05) from rest with mild MS, but not with moderate or severe MS. The decrease in exercise LVEF was due to a decrease in exercise end-diastolic volume of 9 +/- 23% and 15 +/- 18% for moderate and severe MS, respectively. Exercise end-systolic volume decreased normally for all degrees of MS severity. Exercise right ventricular (RV)EF did not increase for any degree of MS severity due to an increase in end-systolic volume. All patients in group II had an RVEF of less than 40%. For this group, severity of MS had no effect on resting LVEF and the response to exercise was similar to group I. We conclude that in patients with MS, resting LVEF is unaffected by MS severity whereas exercise LVEF decreases with increased severity of MS due to impaired diastolic filling.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

[Electrophysiologic evaluation of athletes with Wolff-Parkinson-White syndrome: induction of supraventricular arrhythmia at rest and under exertion with transesophageal atrial electrostimulation].

The most suitable approach to the athletes with WPW is controversial. Therefore 66 symptom-free athletes with WPW and without heart disease (53 M, 13 F, mean age 21.98 yrs, min 12--max 44) underwent a study protocol whose end-point was the induction of supraventricular tachyarrhythmia, i.e. atrial fibrillation or, if not possible, atrial flutter or atrial tachycardia at rest and during ergometric stress test. The athletes with shortest R-R interval between preexcited beats less than or equal to 240 ms at rest and/or less than or equal to 210 ms during exercise were judged as being at risk i.e. no fit for sport activity. The end-point was reached in 64/66 athletes (in 62 atrial fibrillation). In 4 athletes with life threatening arrhythmia induced at rest the evaluation during exercise was not performed. According to the evaluation at rest we were able to identify only 18 athletes (28.1%) as being at risk, while according to the complete study protocol 26 athletes (40.6%) were judged as such. In 23/64 athletes (36%) this judgement was discordant with the usual non invasive evaluation (i.e. Holter monitoring, ergometric stress test, ajmaline test). During induced atrial fibrillation no significant difference, was found between the percentage of preexcited beats at rest and during exercise. On the average, 40 min. are required for performance of this study protocol (if the induced arrhythmia lasts less than 5 min.). According to our results we conclude: a) the non invasive assessment of the WPW athletes is unsatisfactory; b) the induction of atrial fibrillation during exercise gives a remarkable increase of the diagnostic power with respect to the assessment only at rest; c) since it is simple to perform and not expensive (in time, staff and cost) and because of its high diagnostic yield, we regard this protocol as fundamental for the electrophysiological evaluation of WPW athletes and also suitable for systematic study of WPW patients.

Adolescent↗
PubMed1979

Resting metabolic rate in obese and normal weight women.

The relationship between resting metabolic rate and different parameters of body size was investigated among 28 female volunteers in the age group of 20--30 years. The resting metabolic rate of the subjects was determined indirectly by measuring the oxygen consumption in a closed circuit, in which the oxygen concentration was stabilised. The fat percentage of the body was determined by densitometry. The population was divided into two groups: the obese, with an average fat percentage of 33.6 and the normal-weight with an average fat percentage of 20.4. Mean values for the resting metabolic rate were 1550 kcal/24 h (6.488 MJ/24 h) for the obese and 1421 kcal/24 h (5.948 MJ/24 h) for the normal-weight group. The resting metabolic rate per kg body weight was lower in the obese than in the normal-weight persons. However, expressed per kg fat-free body mass, energy expenditure under resting conditions in the obese was higher than in the normal-weight. No single body parameter seems to be suitable in the explantation of RMR in women with substantially different fat content. The best prediction of resting metabolic rate in this population of obese and normal-weight women is obtained when both fat-free mass and fat mass are used as independent variables in a linear regression equation.

Adipose Tissue↗
PubMed1984

[Dependence of the entry of NIH 3T3 cells into a period of DNA synthesis on the duration of their preliminary resting state].

Using radioautography and cell fusion technique, we studied cell kinetics and functional properties of NIH 3T3 mouse fibroblasts stimulated to proliferate after being quiescent for 3, 7 and 14 days. The resting state was achieved by cultivating cells in the medium with 0.5% of serum, the stimulation being achieved by replacement of the depleted medium for a fresh one containing 10% of serum. It was found that the longer cells had been kept resting, the longer their prereplicative period lasted after the stimulation, the lesser was the fraction of cells that entered the S-period. Cell-fusion experiments revealed that the ability of the resting nuclei to suppress the onset of DNA synthesis in the nuclei of stimulated cells in heterodikaryons increased as the cells stayed in the resting state before fusion, and that the period of suppression was prolonged. The data are consistent with the idea of cells going into deeper resting states. It may be concluded that the resting cells undergo a gradual development resulting in the changes of their functional properties.

Animals↗
PubMed1984

Differences between the effects of phenylephrine and other inotropic interventions on post-rest contraction in guinea-pig ventricular strips.

The influence of several inotropic interventions on the strength of the post-rest contraction (PCR) was studied in isolated guinea-pig ventricular strips. In preparations stimulated at 1 Hz and incubated in 3.6 mM Ca++, the PRC-maximum potentiation was obtained after a rest interval of 2 sec (optimum resting time: ORT); a post-rest potentiation was present until 15 sec of rest. An increase in stimulation rate and in Ca++ concentration induced a shift in the ORT towards 15-20 sec, and an increase in the potentiation of PRC. At a low stimulation rate (0.33 Hz) the PRC was lower than steady-state contraction (SSC) at all rest intervals tested. Phenylephrine (5 X 10(-6) M) did not modify the ORT either at 1 or 2.5 Hz, and reduced the height of PRC at 0.33, 1 and 2.5 Hz. These results are discussed in terms of the different effects induced by the various inotropic interventions on cellular calcium availability.

Animals↗