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At least 91 records · Page 5Linked to original sources
PubMed1988

The efficacy of the addition of nifedipine in patients with mixed angina compared to patients with classic exertional angina: a multicenter, randomized, double-blind, placebo-controlled clinical trial.

Episodes of myocardial ischemia in patients with coronary artery disease may be due to transient increases in coronary vasomotor tone superimposed on a fixed atherosclerotic obstruction. The purpose of this study was to determine whether identification of the clinical pattern of angina could predict the therapeutic response to the addition of nifedipine to a regimen of beta blockers and/or long-acting nitrates. Seventy-two patients with stable exertional angina were divided into two groups: "classic exertional angina" (17 patients), defined as exertional angina with a stable threshold; and "mixed angina" (55 patients), defined as exertional angina provoked by a variable threshold and/or at least two episodes of rest angina within the 3 months prior to screening. Patients were studied with nifedipine and placebo in a 6-week, double-blind, crossover design that used serial anginal diaries, exercise treadmill tests, and 24-hour ambulatory ECG monitoring. In patients with mixed angina, nifedipine reduced the frequency of angina compared to that during placebo treatment (13.1 vs 9.9 episodes/3 weeks, p less than 0.01) and reduced nitroglycerin consumption (11.7 vs 7.5 tablets/3 weeks, p less than 0.05); while in patients with classic exertional angina, nifedipine had no symptomatic effect (7.9 vs 6.8 anginal episodes/3 weeks, NS; 6.4 vs 5.8 nitroglycerin tablets/3 weeks, NS). Patients in both groups experienced a significant decrease in the manifestations of ischemia during exercise testing. Patients with mixed angina experienced a reduction in the daily frequency of painful episodes of ST segment depression during nifedipine treatment compared to placebo (0.6 vs 0.2 episodes, p less than 0.05), but there was no effect on the frequency of episodes of silent ischemia (4.2 vs 3.4 episodes, NS). In patients with classic exertional angina, the addition of nifedipine had no effect on any measure of ambulatory ischemia. We conclude that patients with mixed angina are more likely to benefit symptomatically from the addition of nifedipine therapy than patients with classic exertional angina. The lack of a consistently preferential response to nifedipine in patients with mixed angina, however, suggests that episodic coronary vasoconstriction may not be the only mechanism responsible for ischemia in these patients, and/or that nifedipine may not necessarily provide additional therapeutic benefit beyond that conferred by a regimen of beta blockers and/or nitrates.

Adrenergic beta-Antagonists↗
PubMed2004

[Exertional compartment syndrome].

OBJECTIVES: To review the literature on chronic exertional compartment syndrome. METHODS: We searched the Medline database with use of the keys words compartment syndrome, exertional, chronic, pressure, and fasciotomy. RESULTS: Exertional compartment syndrome is characterized by pain on exertion, which recedes at rest, and by excessive increase in compartment intramuscular pressure. Intramuscular pressure measurement is the reference diagnostic tool, but it has not been standardized or evaluated. Pressure observed during the first 5 min after exertion stops is more often used in diagnosis. The first studies of noninvasive investigations (magnetic resonance imaging, thallium single-photon emission tomographic imaging, near infrared spectroscopy) revealed their inadequate diagnostic value. The pathophysiological features of exertional compartment syndrome remain unclear: increased muscle bulk, fascia thickness and stiffness, stimulation of fascial sensory stretch-receptors, poor venous return, micromuscular injuries, and small clinical myopathic abnormalities. Treatment includes decreased sport activity or fasciotomy with partial fasciectomy. Several authors have used endoscopically assisted fasciotomy, which retrospective studies have shown to be successful. Long-term outcome studies could investigate the persistence of exertional minor pain and recurrence of the compartment syndrome with this treatment. CONCLUSION: Further studies are required to understand the physiopathology, standardize the intramuscular pressure test and evaluate the pressure threshold values, evaluate noninvasive investigations and specify the long-term outcome of fasciotomy.

Chronic Disease↗
PubMed1997

Bilateral acute-on-chronic exertional lateral compartment syndrome of the leg: a case report and review of the literature.

PURPOSE: We report a previously undescribed case of bilateral acute exertional compartment syndrome of the lateral compartment arising from pre-existing chronic exertional compartment syndromes. CASE SUMMARY: A 21-year-old football player had a 1-year history of bilateral chronic exertional compartment syndrome. One day after practice his usual symptoms progressed instead of abated and he presented at 3:00 AM with bilateral acute lateral compartment syndromes. His lateral compartment pressures were > 100 mm Hg. Emergency surgical releases were performed and the patient recovered well with full return to competitive football in 4 weeks. DISCUSSION: No prior case of acute-on-chronic exertional compartment syndrome of the lateral compartment has been reported. In addition, this is a case of bilateral acute exertional compartment syndrome. The literature is reviewed with discussion of differential diagnosis, distribution, pathophysiology, and treatment of exertional compartment syndrome. RELEVANCE: Failure to recognize and emergently treat progression of a chronic to an acute exertional compartment syndrome can be devastating.

Adult↗
PubMed2004

Balance Recovers Within 20 Minutes After Exertion as Measured by the Balance Error Scoring System.

OBJECTIVE: To determine a balance recovery timeline after a functional exertion protocol using the Balance Error Scoring System (BESS). DESIGN AND SETTING: Five subject groups (4 test, 1 control) were tested 3 times during 1 session: once before the exertion protocol (pretest) and twice after the exertion protocol (posttest I and posttest II). Posttest I occurred at staggered intervals of 0, 5, 10, and 15 minutes, depending on experimental group assignment, and posttest II occurred at 20 minutes. SUBJECTS: One hundred subjects (80 test, 20 control) volunteered to participate in this study. None of the subjects had a balance disorder, mild head injury, or lower extremity injury in the 6 months before testing. MEASUREMENTS: We assessed balance using the BESS, assigning a score for each stance-surface condition. RESULTS: We found a significant decrease in BESS performance after the exertion protocol in all test groups, with exertion having the greatest effect on the tandem and single-leg stance conditions. All subjects recovered by posttest II, which was administered 20 minutes after cessation of the exertion protocol. CONCLUSIONS: Athletic trainers need to be aware of the effect of exertion when administering the BESS after physical activity. Athletic trainers can expect the BESS performance of healthy athletes to return to baseline levels within 20 minutes of rest.

Journal Article↗
PubMed2000

Quadriceps activation and perceived exertion during a high intensity, steady state contraction to failure.

The ability to sustain a high-intensity, steady-state muscle contraction may have differential effects on neuromuscular activation and perceived exertion. The purpose of this study was to examine changes in neuromuscular activation and perceived exertion at a near-maximal steady-state contraction of the quadriceps in healthy men. Seventeen healthy, college-aged male volunteers were studied during isometric contractions equivalent to 80% of the maximum voluntary contraction (MVC). Perceived exertion was measured with a modified category-ratio scale (CR-10). The CR-10 scale was anchored with one high anchor at 100% MVC and one low anchor at 10% MVC. Subjects then performed an 80% MVC for as long as they could sustain it. Subjects were asked to rate the feelings in their quadriceps every 5 s during the contraction. The results demonstrated significant increases in neuromuscular activation of the vastus medialis and vastus lateralis muscles (P < 0.05) during the 80% MVC, but there were no significant muscle by time interactions. The results also demonstrated a significant increase (P < 0.05) in perceived exertion during the 80% MVC. Neuromuscular activation of both muscles, and perceived exertion, were found to increase in linear (P < 0.05) and quadratic (P < 0.05) trends. Alterations in motor unit discharge properties or impairments in muscle fiber membrane excitability may account for nonlinear increases in vastii muscle activation and perceived exertion.

Adult↗
PubMed1994

Moderate exertion lasting only seconds reduces intraocular pressure.

Intense physical exertion is known to reduce intraocular pressure (IOP). However, the effect of physical exertion on IOP in the first few seconds after beginning exertion has not been studied previously. IOP was determined twice within 15 s in 32 healthy, young men. Seventeen performed six deep knee bends within 8-10 s preceding the second IOP measurement, while 15 did not. The mean reduction in IOP immediately after such brief and moderate exertion was 1.9 +/- 0.3 mmHg, compared with 0.8 +/- 0.2 mmHg in the control group. The difference between both groups was statistically significant. Thus, even moderate physical exertion may reduce IOP. As the relative decrease in IOP correlated with the relative increase in heart rate, the observed reduction in IOP after brief, moderate physical exertion may be due to sympathetic activity.

Adult↗
PubMed1995

Circulating angiotensin-converting enzyme, von Willebrand factor antigen and thrombomodulin in exertional heat stroke.

1. Military recruits frequently succumb to exertional heat stroke during intensive training. Since widespread endothelial injury is often associated with exertional heat stroke, the relationship between changes in three circulating endothelial cell markers (angiotensin-converting enzyme, von Willebrand factor antigen and thrombomodulin) and exertional heat stroke was studied. 2. Twelve recruits who had succumbed to exertional heat stroke during basic physical training (5000 m running) were included in the study. Another 10 age-matched healthy subjects who had gone through the same physical training regimen were selected as controls. 3. Blood was withdrawn on admission and on discharge for analyses of angiotensin-converting enzyme, von Willebrand factor antigen and thrombomodulin. Other physiological parameters and biochemical analyses reflecting renal and liver functions were also recorded. 4. Our results indicated that these subjects with exertional heat stroke exhibited impaired liver function as revealed by the significant elevation of both serum glutamic oxaloacetic transaminase (P < 0.05) and serum glutamic pyruvic transaminase (P < 0.05) as compared with normal healthy control subjects. Unfortunately, these values remained mostly somewhat elevated on discharge, although serum glutamic oxaloacetic transaminase was reduced dramatically. Indices of kidney functions, including creatinine clearance and uric acid and phosphorus secretion, were not significantly different from those observed in healthy controls. 5. Circulating angiotensin-converting enzyme activities in exertional heat stroke patients on admission were significantly lower than in normal subjects (10.68 +/- 2.15 versus 21.21 +/- 3.18 nmol hippuric acid min-1 ml-1, P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2000

Contributions of local and central sensations to the perception of exertion during cycling: effects of work rate and cadence.

There is evidence to suggest that perception of exertion during exercise is based on both local and central sensations. The aim of the present experiment was to determine the relative contributions of different sensations to overall perceived exertion during cycling. Eighteen trained cyclists pedalled on a cycle ergometer for 4 min at each of three work rates (100, 150 and 200 W) and cadences (50, 70 and 90 rev x min(-1)). At the end of each bout, they used Borg's category-ratio (CR-10) scale to rate their overall perceived exertion, leg muscle pain, knee pain, breathlessness and heart beat intensity. The results indicated that cadence only influenced local sensations (muscle pain and knee pain), which were significantly higher at slower pedalling rates. Neither overall perceived exertion nor central sensations (breathlessness and heart beat intensity) were significantly affected by cadence. In contrast, increases in work rate were associated with higher ratings for all sensations. Further analyses revealed that variations in these overall ratings of perceived exertion as a function of work rate were accounted for by variations in ratings of muscle pain and breathlessness. The general implication is that perceived exertion during cycling derives from a combination of muscle and respiratory sensations.

Adult↗
PubMed2006

Building-site camps and extended work hours: A two-week monitoring of self-reported physical exertion, fatigue, and daytime sleepiness.

Large-scale construction work often requires people to work longer daily hours and more than the ordinary five days in a row. In order to minimize transportation times and optimize the use of personnel, workers are sometimes asked to live in temporary building-site camps in the proximity of the work site. However, little is known about the biological and psychological effects of this experience. The objective of the present study was to investigate whether exposure to long work hours and extended workweeks while living in building-site camps in between work shifts was associated with a build-up of increased complaints of poor sleep, daytime sleepiness, physical exertion, and fatigue across a two-week work cycle. Two groups of construction workers were examined. The camp group of 13 participants (mean age: 42+/-11 S.D. yrs) lived in building-site camps and worked extended hours (between 07:00 and 18:00 h) and extended workweeks (six days in a row, one day off, five days in a row, nine days off). The home group of 16 participants (mean age 40+/-9 yrs) worked ordinary hours between 07:00 and 15:00 h and returned home after each workday. Self-ratings of daytime sleepiness (Karolinska Sleepiness Scale), physical exertion (Borg CR-10), and mood were obtained six or seven times daily during two workweeks. Fatigue ratings were obtained once daily in the evening, and ratings of sleep disturbances were obtained once daily in the morning with the Karolinska Sleep Diary. Data were evaluated in a repeated measures design. The results showed that both groups reported a similar level of daytime sleepiness, physical exertion, and mood across workdays and time points within a workday (all three-way interactions had p>0.898). Although the home group reported earlier wake-up times, the pattern of sleep disturbance ratings across the workdays did not differ between the groups. Both groups reported few sleep disturbances and good mood. However, the camp group reported higher physical exertion already at the start of work and showed a more gentle increase in ratings during the work shift and a smaller decline between the end of work and bedtime. The camp group also reported higher fatigue scores than the home group. However, none of the groups showed signs of increasing ratings in the progress of the two workweeks. For both groups, the ratings of daytime sleepiness formed a U-shaped pattern, with the highest scores at awakening and at bedtime. Yet, the camp group reported higher daytime sleepiness than the home group at lunch break and at the second break in the afternoon. In conclusion, there were no signs of fatigue build-up or accumulation of daytime sleepiness, physical exertion, or sleep disturbances in either group. Despite the fact that the camp group showed some signs of having trouble in recuperating in between work shifts, as indicated by the higher physical exertion ratings at the start of work, higher fatigue scores, and higher daytime sleepiness, the results constitute no real foundation for altering the camp group's current work schedule and living arrangements.

Adult↗
PubMed1997

Blood lactate threshold and type II fibre predominance in patients with exertional heatstroke.

OBJECTIVES: Severe damage to skeletal muscle is usually seen in patients with exertional heatstroke. Thirty seven young military recruits with exertional heatstroke in Taiwan from 1992 to 1995 were studied to evaluate changes in muscle pathology and blood lactate with exercise. METHODS: A biopsy sample of the vastus lateralis was taken from recruits within 10 days of the initial presentation. Results were compared with those from 15 controls matched for age and sex. During the recovery period, 90-150 days after exertional heatstroke, 29 patients participated in a constant work load test on the treadmill to assess their blood lactate threshold, and a second biopsy sample was taken. Each biopsy was examined histologically for pathology, distribution of fibre types, and fibre diameter. RESULTS: Twenty four of the 37 patients with exertional heatstroke developed rhabdomyolysis and 18 of these had type II fibre predominance in their muscle biopsy. The patients with type II fibre predominance had a higher tendency to develop rhabdomyolysis (chi 2 = 6.84, P < 0.01). The time required to reach a blood lactate threshold during a constant treadmill work load after recovery was significantly shorter in the patients with exertional heatstroke who had type II fibre predominance (P < 0.01). There was a positive correlation between the highest value of blood lactate and the percentage of type II fibres in all tested subjects (r = 0.82, P < 0.01). CONCLUSION: Patients with type II fibre predominance are more susceptible to exertional heatstroke and tend to have a higher blood lactate concentration and a shorter time to reach blood lactate threshold under a treadmill load test.

Adult↗
PubMed2005

Exertional leg pain in patients with and without peripheral arterial disease.

BACKGROUND: Although exertional leg pain is a hallmark of peripheral arterial disease (PAD) and can occur in persons without PAD, symptom variation has received inadequate attention. METHODS AND RESULTS: Three cohort studies were combined for cross-sectional analysis. The San Diego Claudication Questionnaire assessed exertional leg pain. PAD was defined as ankle brachial index (ABI) < or =0.90 or history of lower-extremity revascularization. Of 3658 subjects, 3629 were analyzed after exclusions. Of these, 24.1% had PAD in 1 or both legs. There was a stepwise decrease in average ABI, from no pain to pain on exertion and rest, noncalf pain, atypical calf pain, and classic claudication (P=0.002). When stratified by PAD, this trend was no longer significant. Legs with ABIs >0.90 and revascularization had pain distributions intermediate between that of normal legs (ABI, 1.00 to 1.39) and legs with ABIs < or =0.90. Compared with normal legs, legs with low-normal (0.91 to 0.99) and high-normal (> or =1.40) ABIs had higher pain rates, suggesting borderline disease and vascular stiffness, respectively. Multivariable logistic regression models showed that ABI was a strong correlate of pain category throughout the ABI range. Independently of ABI, age, male sex, diabetes, smoking history, high body mass index, myocardial infarction, and previous revascularization were all significant correlates of exertional leg pain. CONCLUSIONS: No category of exertional leg pain was sufficiently sensitive or specific for routine PAD diagnosis. Legs with low-normal and high-normal ABIs appeared to have ischemic leg pain; thus, a "normal ABI" is likely to range from 1.00 to 1.39. In addition to ABI, several risk variables were independent correlates of exertional leg pain.

Aged↗
PubMed1996

Cough, exertional, and sexual headaches: an analysis of 72 benign and symptomatic cases.

We analyzed our experience with cough, exertional, and vascular sexual headaches, evaluated the interrelationships among them, and examined the possible symptomatic cases. Seventy-two patients consulted us because of headaches precipitated by coughing (n = 30), physical exercise (n = 28), or sexual excitement (n = 14). Thirty (42%) were symptomatic. The 17 cases of symptomatic cough headache were secondary to Chiari type I malformation, while the majority of cases of symptomatic exertional headaches and the only case of symptomatic sexual headache were secondary to subarachnoid hemorrhage. Although the precipitant was the same, benign and symptomatic headaches differed in several clinical aspects, such as age at onset, associated clinical manifestations, or response to pharmacologic treatment. Although sharing some properties, such as male predominance, benign cough headache and benign exertional headache are clinically separate conditions. Benign cough headache began significantly later, 43 years on average, than benign exertional headache. By contrast, our findings suggest that there is a close relationship between benign exertional headache and benign vascular sexual headache. We conclude that benign and symptomatic cough headaches are different from both benign and symptomatic exertional and sexual headaches.

Adolescent↗
PubMed2004

The effects of rest interval length on ratings of perceived exertion during dynamic knee extension exercise.

The objective of this study was to examine the effects of rest interval length on perceived exertion and during 3 sets of 10 inertial knee extension repetitions. Thirty healthy men (n = 15) and women (n = 15) volunteers were randomly assigned to 1 of 3 groups (1-, 2-, or 3-minute rest interval length) following the establishment of each subject's 1 repetition maximum (1RM) for inertial knee extension exercise. Subjects in each group performed 3 sets of 10 repetitions at 70% of a theoretical 10RM (based on each subject's 1RM), with a 1-, 2-, or 3-minute rest interval between each set. Perceived exertion was recorded, via the Borg category-ratio scale, from each subject after each repetition of each set. The results demonstrated no significant rest interval length effect on perceived exertion across the 3 sets of 10 repetitions. The results revealed a significantly higher perceived exertion value following the first repetition in set 3 as compared to sets 2 and 1 in all groups. The increase in perceived exertion within each set, as described by the slope, was found to be significantly lowest in set 1, as compared to sets 2 and 3. The major findings of this study demonstrate that perceived exertion significantly increases in a similar manner across 3 sets of 10 knee extension repetitions, despite rest interval lengths of 1-3 minutes.

Adult↗
PubMed2006

Perimesencephalic nonaneurysmal subarachnoid hemorrhage caused by physical exertion.

The clinical characteristics of perimesencephalic nonaneurysmal subarachnoid hemorrhage (SAH) caused by physical exertion were analyzed to investigate the causes and mechanisms of perimesencephalic nonaneurysmal SAH. Nine of 209 patients with spontaneous SAH were identified as having perimesencephalic nonaneurysmal SAH. Perimesencephalic nonaneurysmal SAH in four males and three females was precipitated by exertion. Age, sex predominance, type of exertion, symptoms, loss of consciousness during bleeding, clinical grade, angiographic spasm, hydrocephalus, delayed ischemic deficit, rebleeding, hypertension, and outcome were evaluated in these seven patients. Outcomes were assessed using the Glasgow Outcome Scale. Patients showed male predominance (57.1%), relatively young age (mean 50 years), low frequency of hypertension (28.6%), good clinical grade (World Federation of Neurological Surgeons grade I or II), and excellent outcomes including no rebleeding, no symptomatic hydrocephalus, and no delayed ischemic deficits. The type of exertion was swimming in two patients, golfing in two patients, heavy lifting in two patients, and bending forward during gymnastics in one patient. Physical exertion including components of the Valsalva maneuver is an important predisposing factor for perimesencephalic nonaneurysmal SAH. Such physical exertion produces increased intrathoracic pressure, which blocks the internal jugular venous return, resulting in elevated intracranial venous pressure or mechanical swelling of the intracranial veins, and leads to venous or capillary breakdown.

Adult↗
PubMed2006

[Masticatory muscle activity during exertion of the back].

PURPOSE: The lower jaw is considered to be fixed during body exercise. However, its mechanism remains to be elucidated. The present study investigated masticatory muscle activity during of the back. METHODS: The subjects were 9 healthy dentulous patients. The maximum back strength of the patients was measured with a back-dynamometer. Muscle activities of the temporal, masseter and digastric muscles during exertion of the back and mastication of peanuts were measured. Muscle activities of the temporal and masseter muscle during maximum voluntary clenching and that of the digastric muscles during exertion of resistance against forced mouth opening were also measured, and maximum voluntary muscle activities were obtained. The relative percentage of each masticatory muscle against maximum voluntary activity was calculated from the data obtained, and muscle activities during exertion of the back, mastication of peanuts and maximum muscle activity were compared. RESULTS: Muscle activities of the temporal, masseter and digastric muscles during exertion of back muscles against maximum voluntary muscle activity were 32.1%, 26.4% and 97.4% respectively. Muscle activities of these muscles during mastication of peanuts against maximum voluntary muscle activity were 40.7%, 36.0% and 17.3% respectively. CONCLUSIONS: Muscle activities during exertion of the back were 30% in the temporal and masseter muscle, and approximately 100% in the digastric muscles. The result suggests that the digastric muscles play a key role in fixing the mandible in all masticatory muscles including jaw-opening and closing muscles. People exert back strength not only in sports but also in daily life. This study demonstrates the stronger involvement of the digastric muscles in fixation of the mandible during exercise than during strong clenching. The results are of interest in terms of mandibular position, occlusal contact and the load on the temporomandibular joint (TMJ) since there is no wide mouth opening.

Adult↗
PubMed2001

Force developmental phase and reliability in explosive and voluntary grip exertions.

The purposes of this study were to clarify the reliability of two types of grip exertions, explosive grip exertion and voluntary grip exertion up to the maximal grip strength and to examine their force patterns using force-time parameters. Subjects were 100 healthy young male volunteers (age: 17.8+/-2.50 yr.) who had no upper limb injury. Grip strength was measured two times with voluntary grip and then two times with explosive grip. 11 parameters derived from the force-time curve were selected to measure the developmental phase of muscle contraction. The reliability of maximal grip strength in explosive and voluntary grip exertions was very high (intraclass correlation = .95, .93). The difference between two trials in explosive grip tended to be smaller than that for voluntary grip, and reliability of the exertion pattern was higher for explosive grip than voluntary grip. The times to reach 90% of the maximal grip strength and the maximal grip strength in explosive grip were shorter than those in voluntary grip. The other 8 force-time parameters had higher values in explosive grip than voluntary grip and higher reliabilities. The force-time parameters reflect the properties of explosive exertion. The results suggest the possibility that static explosive strength could be evaluated using these force-time parameters.

Adolescent↗
PubMed1998

Rodent data and general hypothesis: antipsychotic action exerted through 5-Ht2A receptor antagonism is dependent on increased serotonergic tone.

The locomotor stimulation induced by the N-methyl-D-aspartate (NMDA) receptor antagonist MK-801 (dizocilpine) in mice was regarded as a model of at least some aspects of schizophrenia. The serotonin synthesis inhibitor dl-p-chlorophenylalanine (PCPA) was used to evaluate the involvement of endogenous serotonin in (a) the induction of MK-801-induced hyperlocomotion in NMRI mice, and (b) the inhibition of MK-801-induced hyperlocomotion by each of five monoaminergic antagonists (M100907, clozapine, olanzapine, raclopride, SCH23390). Further, brain monoaminergic biochemistry was characterised in rats and mice after various drug treatments. PCPA pretreatment did not significantly reduce MK-801-induced hyperlocomotion in any of the experiments performed; however in a meta-analysis of six experiments, the locomotion displayed by MK-801-treated animals was diminished 17% by PCPA pretreatment. The selective 5-HT2A receptor antagonist M100907 exerted a dose-dependent inhibition of MK-801-induced hyperlocomotion. This effect was abolished in mice pretreated with PCPA, but could be restored in a dose-dependent manner by restitution of endogenous 5-HT by means of 5-hydroxytryptophan (5-HTP). On the other hand, the inhibition of MK-801-induced hyperlocomotion exerted by the selective dopamine D-2 receptor antagonist raclopride or the dopamine D-1 receptor antagonist SCH23390 was unaffected by PCPA pretreatment. The antipsychotics clozapine and olanzapine displayed a split profile. Hence, the inhibitory effect on MK-801-induced hyperlocomotion exerted by low doses of these compounds was diminished after PCPA pretreatment, while inhibition exerted by higher doses was unaffected by PCPA. These results suggest that (1) MK-801-induced hyperlocomotion is accompanied by an activation of, but is not fully dependent upon, brain serotonergic systems. (2) In the hypoglutamatergic state induced by MK-801, endogenous serotonin exerts a stimulatory effect on locomotion through an action at 5-HT2A receptors, an effect that is almost completely counterbalanced by a concomitant inhibitory impact on locomotion, mediated through stimulation of serotonin receptors other than 5-HT2A receptors. M100907, by blocking 5-HT2A receptors, unveils the inhibitory effect exerted on locomotion by these other serotonin receptors. (3) Dopamine D-2 receptor antagonistic properties of antipsychotic compounds, when they come into play, override 5-HT2A receptor antagonism. Possible implications for the treatment of schizophrenia with 5-HT2A receptor antagonists are discussed. It is hypothesized that treatment response to such agents is dependent on increased serotonergic tone.

3,4-Dihydroxyphenylacetic Acid↗
PubMed2006

Triggering of acute coronary syndromes by physical exertion and anger: clinical and sociodemographic characteristics.

OBJECTIVE: To investigate the role of vigorous physical exertion and anger as triggers of acute coronary syndromes (ACS) and to identify the clinical and sociodemographic correlates of triggering. DESIGN: Prospective observational clinical cohort study. SETTING: Four coronary care units in the London area. PATIENTS: 295 men and women with electrocardiographically and biochemically verified ACS. MAIN OUTCOME MEASURES: Physical exertion in the 1 h and anger in the 2 h before symptom onset were assessed with structured interviews. Control periods were the equivalent hours one day earlier and usual rates over the past six months. Data were analysed by case-crossover methods. RESULTS: Physical exertion was reported by 10% and anger by 17.4% of patients in the hazard period. The risk of ACS onset after physical exertion compared with light or no activity was 3.50 (95% confidence interval (CI) 1.37 to 10.6). The risk of onset with anger was 2.06 (95% CI 1.12 to 3.92). Physical exertion during the hazard period was related to an absence of premonitory symptoms, presentation with an ST elevation myocardial infarction (STEMI), low socioeconomic deprivation and higher future cardiovascular risk. Anger during the hazard period was more common in younger, socioeconomically deprived patients who presented with a STEMI. CONCLUSIONS: Triggers are relevant across the spectrum of ACS. The distinct clinical and sociodemographic factors associated with physical exertion and anger suggest that different pathophysiological processes may be involved.

Age Factors↗