Muscle hypertrophy with large-scale weight loss and resistance training

The combined effects of exercise and energy restriction on changes in body fat and fat-free mass (FFM) are controversial. This study was conducted to determine whether muscle hypertrophy is possible during weight loss. Fourteen obese females received a 3360-kJ/d liquid diet for 90 d. Seven subjects received a weight training (WT) regimen and seven subjects remained sedentary (C). Biopsy samples were obtained from the vastus lateralis muscle at baseline and after 90 d of treatment. The average weight loss over the 90-d period was 16 kg with approximately 24% of the weight loss from FFM and 76% from fat. The amount and composition of the weight loss did not differ between WT and C groups. The cross-sectional area of slow twitch and fast twitch fibers was unchanged by treatment in C subjects but significantly increased in WT subjects. It appears that weight training can produce hypertrophy in skeletal muscle during severe energy restriction and large-scale weight loss.

In vivo monoamine release during naloxone-precipitated morphine withdrawal

There is much evidence from animal work suggesting that the release of noradrenaline (NA) in the brain increases during naloxone-precipitated morphine withdrawal, but the evidence in favour of changes in release of 5-hydroxytryptamine (5-HT) and dopamine (DA) is contradictory. Here we demonstrate, using in vivo microdialysis, that whilst there is a considerable increase (300%) in release of NA in hippocampus precipitated by naloxone in morphine-dependent rats, there is no change in the release of either 5-HT (in hippocampus) or DA (in nucleus accumbens). These results are consistent with suggestions that the symptoms of morphine withdrawal in rats are due primarily to an increase in central NA release.

The novel 5-HT1A receptor antagonist, SDZ 216-525, decreases 5-HT release in rat hippocampus in vivo

1. Recent evidence suggests that the novel compound SDZ 216-525 is a selective and possibly silent 5-HT1A receptor antagonist. Here we have examined the action of SDZ 216-525 on central 5-HT1A autoreceptor function. The experiments involved measurement of drug effects on extracellular 5-HT in the ventral hippocampus of the chloral hydrate anaesthetized rat by use of microdialysis. 2. Acute injection of SDZ 216-525 (0.1, 0.3, 1.0 and 3 mg kg-1, s.c.) caused a dose-related decrease in 5-HT output with an estimated ED50 of at least 0.3 mg kg-1. This ED50 value is 20-30 times greater than ED50 values previously obtained for 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT) and NAN-190. In comparison, SDZ 216-525 is reported to have slightly higher affinity for the 5-HT1A site than 8-OH-DPAT and NAN-190. 3. The inhibitory effect of SDZ 216-525 (1 mg kg-1, s.c.) on 5-HT was blocked by the 5-HT1/beta-adrenoceptor antagonist, (-)-pindolol (8 mg kg-1, s.c.) but not by a combination of the beta 1- and beta 2-selective adrenoceptor antagonists metoprolol and ICI 118,551 (4 mg kg-1, each). 4. Although in several experimental models SDZ 216-525 has high affinity, selectivity and lacks intrinsic activity at the 5-HT1A receptor, our experiments show that the drug decreases extracellular 5-HT in ventral hippocampus of the chloral hydrate anaesthetized rat via a pindolol-sensitive mechanism. We conclude that either SDZ 216-525 promotes (with low potency in vivo) 5-HT1A receptor/G-protein interactions, or that the 5-HTlA autoreceptor is a 5-HT1A receptor subtype different from the postsynaptic 5-HT1A receptor.

In vivo microdialysis evidence for central serotonin1A and serotonin1B autoreceptor blocking properties of the beta adrenoceptor antagonist (-)penbutolol

Recently, we found that the beta 1/beta 2 adrenoceptor blocking agent (-)penbutolol prevents behavioral and biochemical actions of the specific serotonin (5-HT)1A agonist (+/-)-8-hydroxy-2-(di-n-propylamino)tetralin. The putative 5-HT1 receptor antagonist profile of (-)penbutolol was further explored in the present study, using in vivo microdialysis methods to assess its effects on central 5-HT release. (+)Penbutolol and (-)pindolol were included for comparison purposes. In contrast to (-)pindolol (8.0 mg/kg s.c.), administration of (-)penbutolol (2.0 or 8.0 mg/kg s.c.) increased hippocampal 5-HT output. The (-)penbutolol-induced 5-HT response was dose-related, stereoselective and Ca(++)-dependent. In addition, the 5-HT response to (-)penbutolol was abolished by omitting the 5-HT reuptake blocker citalopram from the perfusion medium, suggesting the need for endogenous 5-HT tone. Local (-)penbutolol (1 microM) perfusion increased the 5-HT output per se, and also blocked 5-HT release suppression caused by the 5-HT1B receptor agonist CP-93,129. Furthermore, (-)penbutolol, but not its (+)antipode, prevented the decrease of 5-HT release induced by the 5-HT1A receptor agonist (+/-)-8-hydroxy-2-(di-n-propylamino)tetralin. By comparison, the 5-HT1 receptor inactive beta adrenoceptor blockers metoprolol (beta 1) and ICI 118,551 (beta 2), given alone or in combination, did not increase 5-HT output and were ineffective in antagonizing the (+/-)-8-hydroxy-2-(di-n-propylamino)tetralin response. The data indicate that (-)penbutolol possesses 5-HT1A and 5-HT1B autoreceptor antagonist properties, and may be a useful tool in studies of central 5-HT receptor-mediated function.

The effects of aerobic exercise on psychological adjustment: a randomized study of sedentary obese women attempting weight loss

This study evaluated the psychological effects of aerobic conditioning in 40 moderately obese, sedentary women participating in a 12-week behavioral weight loss program. Participants were randomly assigned to a no-exercise or moderate walking condition. Emotional impact of the treatment was assessed in two ways: (1) Subjects reported subjective mood prior to each eating episode and (2) the SCL-90-R was administered before and after the program. Exercisers lost more weight and body fat than non-exercisers. Both groups of subjects showed numerous improvements in mood as a result of participating in the weight loss program. Exercise had no specific differential effect on emotions as measured by daily mood ratings or the SCL-90-R. Exercise did not appear to add appreciably to the psychological benefits of losing weight in this sedentary obese population. Future studies utilizing longer periods of aerobic exercise training, larger sample size, and exercise specific measures are recommended.

Comparison of the effect of buspirone and 1-(2-pyrimidinyl)-piperazine on cerebral glucose utilization in the rat

The novel anxiolytic and antidepressant, buspirone, and its main metabolite 1-(2-pyrimidinyl)-piperazine (1-PP), which is pharmacologically active, were examined for their effect on regional cerebral glucose utilization in awake rats using quantitative 2-deoxyglucose autoradiography. At a dose of 1 mg/kg, buspirone reduced glucose utilization in the hippocampus by approximately 15%, whilst 1-PP at the same dose had no effect. In comparison, at a higher dose, 10 mg/kg of both buspirone and 1-PP decreased glucose utilization in the hippocampus by 20% and 27%, respectively. In addition, widespread reductions in local cerebral glucose utilization were noted with this higher dose of 1-PP; such generalized effects are compatible with those reported for alpha 2 adrenoceptor antagonists. Buspirone at 1 and 10 mg/kg increased glucose utilization by 40% and 65%, respectively, in the lateral habenular nucleus, whilst 1-PP at 1 and 10 mg/kg had no effect. The findings suggest that buspirone's effects on glucose utilization cannot be attributed to 1-PP, unless high doses of buspirone are administered.

Towards integrative audit: a partnership for quality

Outlines the gradual process which led to the development of the Sunderland Integrative Audit System. Centred around the Patient's Charter rights and standards, the various modules used together form a patient-centred, multidisciplinary approach to audit that can be used to monitor a contract, clinical directorate or specialty. Founded on the principle that health care is a complex, interactive process, the system seeks to establish the extent to which the patient experiences an "integrated" service by examining the interfaces between departments, professionals and services. Extensive piloting in diverse fields has found the system capable of being used in a variety of hospital and community settings.

Selective 5-HT1A and 5-HT2 receptor-mediated adrenocorticotropin release in the rat: effect of repeated antidepressant treatments

The 5-HT receptor agonists, 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) and 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) produced dose-dependent increases in plasma adrenocorticotropin (ACTH) in the male rat by activation of 5-HT1A and 5-HT2 receptors respectively. The ACTH response to DOI was enhanced by repeated administration of electroconvulsive shock (five over 10 days) but abolished by the tricyclic antidepressant, amitriptyline (20 mg/kg for 14 days). In contrast 21 days lithium treatment failed to alter DOI-induced ACTH release. Neither repeated electroconvulsive shock, nor amitriptyline, nor lithium altered the ACTH response to 8-OH-DPAT. These data are consistent with results from ligand binding and behavioural studies which suggest that the sensitivity of brain 5-HT2 receptors is increased by repeated electroconvulsive shock but attenuated by tricyclic antidepressant treatment. In contrast, our data suggest that the antidepressant treatments studied do not alter the sensitivity of the 5-HT1A receptors involved in ACTH release.

Evidence that 5-HT2 receptor activation decreases noradrenaline release in rat hippocampus in vivo

1. Recent electrophysiological studies have shown that 5-HT2/5-HT1C receptor agonists inhibit the electrical activity of noradrenergic neurones in the rat locus coeruleus. Here we examine the effect of various agonists and antagonists of 5-HT2/5-HT1C receptors on noradrenaline release in hippocampus of anaesthetized rats using microdialysis. 2. Subcutaneous administration of the 5-HT2/5-HT1C receptor agonist, 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI: 0.2 and 0.5 mg kg-1), caused a marked decrease (50% of pre-drug levels 60 min after injection) of noradrenaline in hippocampal dialysates which was long-lasting (greater than 120 min). Noradrenaline output also decreased in response to administration of the structural analogue of DOI, 1-(2,5-dimethoxy-4-bromophenyl)-2-aminopropane (DOB: 1 mg kg-1, s.c.). 3. The effect of DOI on noradrenaline output was prevented by pretreatment with the 5-HT2/5-HT1C receptor antagonist, ritanserin (0.4 mg kg-1, s.c.). Spiperone (0.2 and 1 mg kg-1, s.c.), a 5-HT2/dopamine D2 receptor antagonist which has low affinity for 5-HT1C receptors, also antagonized the effect of DOI (0.5 mg kg-1, s.c.). Sulpiride (50 mg kg-1, s.c.), a dopamine D2 receptor antagonist did not alter the response to DOI (0.5 mg kg-1, s.c.). 4. Both the non-selective 5-HT receptor agonist, quipazine (1 mg kg-1, s.c.), and the 5-HT-releasing agent, p-chloroamphetamine (2 mg kg-1, s.c.), decreased noradrenaline release in hippocampus and these effects were antagonized by pretreatment with ritanserin (0.4 mg kg-1, s.c.).5. Our data suggest that in vivo, noradrenaline release in hippocampus is inhibited by 5-HT2 receptor activation. This effect is probably associated with a decrease in noradrenergic neuronal activity.

The putative 5-HT1A antagonist BMY 7378 blocks 8-OH-DPAT-induced changes in local cerebral glucose utilization in the conscious rat

It has previously been shown that the 5-HT1A agonist, 8-OH-DPAT, caused discrete changes in cerebral glucose utilization in the rat, as assessed by quantitative 2-deoxyglucose autoradiography. Here, the effect of the putative 5-HT1A antagonist, BMY 7378, on regional cerebral glucose utilization was examined, when injected alone and in rats treated with 8-OH-DPAT. In control rats, BMY 7378 (5 mg/kg, s.c.) markedly increased glucose utilization in the lateral habenular nucleus and moderately reduced glucose utilization in the hippocampal formation. Pretreatment with BMY 7378 (5 mg/kg) significantly attenuated the reductions in glucose utilization in the hippocampus, entorhinal, piriform and cingulate cortex, induced by 8-OH-DPAT (0.25 mg/kg). The 8-OH-DPAT-induced increase in glucose utilization in the copula pyramis, that is putatively associated with the appearance of the 5-HT behavioural syndrome, was also blocked by BMY 7378, as was the behavioural syndrome. In summary, BMY 7378 produced few of the discrete changes in cerebral glucose utilization that are seen with 8-OH-DPAT. However, many of the changes induced by 8-OH-DPAT were reversed by BMY 7378. These data are consistent with the hypothesis that the effects of 8-OH-DPAT on regional cerebral glucose utilization are mediated by 5-HT1A receptors.

Effect of naloxone-precipitated morphine withdrawal on noradrenaline release in rat hippocampus in vivo

Here we investigated the effect of naloxone-precipitated morphine withdrawal on the release of noradrenaline in hippocampus of the anaesthetised rat. Naloxone (1 mg/kg i.p.) injected 3 and 24 h, but not 3 weeks, after eight daily injections of morphine, induced an immediate increase in hippocampal noradrenaline release. This striking effect of naloxone was markedly attenuated by pretreatment with clonidine (0.1 mg/kg s.c.). These findings provide direct evidence for a marked release of noradrenaline in hippocampus during opiate withdrawal in vivo.

The role of breakfast in the treatment of obesity: a randomized clinical trial

Fifty-two moderately obese adult women were stratified according to their baseline breakfast-eating habits and randomly assigned a weight-loss program. The no-breakfast group ate two meals per day and the breakfast group ate three meals per day. The energy content of the two weight-loss programs was identical. After the 12-wk treatment, baseline breakfast eaters lost 8.9 kg in the no-breakfast treatment and 6.2 kg in the breakfast treatment. Baseline breakfast skippers lost 7.7 kg in the breakfast treatment and 6.0 kg in the no-breakfast treatment. This treatment-by-strata-by-time interaction effect (P less than 0.06) suggests that those who had to make the most substantial changes in eating habits to comply with the program achieved better results. Analyses of behavioral data suggested that eating breakfast helped reduce dietary fat and minimize impulsive snacking and therefore may be an important part of a weight-reduction program.

Clonidine but not nifedipine prevents the release of noradrenaline during naloxone-precipitated opiate withdrawal: an in vivo microdialysis study in the rat

In this study we have examined whether the alpha 2-adrenoceptor agonist clonidine and the calcium channel antagonist nifedipine firstly inhibit the naloxone-precipitated withdrawal syndrome in morphine-dependent rats and secondly reduce central noradrenaline release during withdrawal. We demonstrate that both clonidine (0.1 mg/kg) and nifedipine (10 mg/kg) attenuate the naloxone-precipitated withdrawal syndrome. Using in vivo microdialysis, we demonstrate that following naloxone the release of noradrenaline, as measured by perfusates from hippocampus, increases 300% in morphine-dependent rats. However, whilst pretreatment with clonidine inhibited this increased noradrenaline release, nifedipine did not. These findings suggest that whilst the action of clonidine in attenuating the morphine withdrawal syndrome may be mediated by decreasing central noradrenaline release, this is not the mechanism by which nifedipine acts.

Effect of 5-hydroxy-L-tryptophan on the release of 5-HT in rat hypothalamus in vivo as measured by microdialysis

The effect of systemic administration of the 5-HT precursor, 5-hydroxy-L-tryptophan (5-HTP) on the release of 5-HT in the lateral hypothalamus of the chloral hydrate-anaesthetized rat in vivo was examined using brain microdialysis. Administration of 5-HTP caused an immediate increase of 5-HT in dialysates, which was long lasting (greater than or equal to 140 min) and dose-dependent (30-100 mg/kg i.p.). When calcium was omitted from the perfusion medium, thereby limiting exocytosis, levels of basal 5-HT were significantly decreased and the 5-HTP-induced response of 5-HT was markedly attenuated. Administration of the 5-HT1A receptor agonist, 8-hydroxy-2-(di-n-propylamino) tetralin (0.25 mg/kg i.p.), which selectively inhibits serotoninergic neuronal activity by activation of the somatodendritic 5-HT autoreceptor, significantly decreased basal levels of 5-HT and markedly attenuated the 5-HTP-induced increase in 5-HT. The data demonstrate that systemic administration of 5-HTP caused an increase in the release of 5-HT in the hypothalamus. Furthermore, this release occurred by a calcium-dependent mechanism (probably exocytosis), was dependent on serotoninergic neuronal activity and predominantly derived from 5-HT neurones. The findings are discussed in relation to the behavioral and neuroendocrine effects of increasing availability of the 5-HT precursor.

Effect of acute administration of L-tryptophan on the release of 5-HT in rat hippocampus in relation to serotoninergic neuronal activity: an in vivo microdialysis study

Here we have used the brain microdialysis method to test the effect of the 5-HT precursor L-tryptophan on 5-HT release. The release of endogenous 5-HT was measured in ventral hippocampus of the anesthetized rat both under basal conditions and when serotoninergic neuronal activity was raised by electrical stimulation of the dorsal raphe nucleus (DRN). Low frequency electrical stimulation of the DRN evoked a frequency-dependent (2-10 Hz) release of hippocampal 5-HT. The electrically evoked release of 5-HT was markedly enhanced by pretreatment with L-tryptophan (50 and 100 mg/kg i.p.). The effect of L-tryptophan on evoked release of 5-HT was dose-related, detectable at low (2 Hz) stimulation frequencies, and became stronger as the stimulation frequency increased. L-Tryptophan (10, 50 and 100 mg/kg i.p.) had no effect on basal output of 5-HT. We conclude from these findings that elevation of 5-HT precursor availability increases 5-HT release in hippocampus in vivo under conditions of increased serotoninergic neuronal activity.

Evidence that the large neutral amino acid L-valine decreases electrically-evoked release of 5-HT in rat hippocampus in vivo

L-Valine competes with tryptophan for transport into the brain and has previously been shown to decrease brain 5-HT synthesis. In the present study, the effect of L-valine on electrically evoked hippocampal 5-HT release was determined in the anaesthetized rat using microdialysis. In control animals two electrical stimulations of the dorsal raphe nucleus 120 min apart (S1 and S2, respectively) released similar amounts of 5-HT. In contrast, in animals which received L-valine (200 mg/kg) between stimulations, S2 released a significantly smaller amount of 5-HT than did S1, although basal 5-HT release was unchanged. The data demonstrate that L-valine decreases the electrically-evoked release of 5-HT in hippocampus in vivo.

Effects of the 5-HT1A partial agonists gepirone, ipsapirone and buspirone on local cerebral glucose utilization in the conscious rat

The azospirones gepirone (10 mg/kg), ipsapirone (10 mg/kg) and buspirone (10 mg/kg) were examined for their effect on regional cerebral glucose utilization in conscious rats using quantitative 2-deoxy-glucose autoradiography. All three 5-HT1A partial agonists reduced glucose utilization in the hippocampus and dentate gyrus by 20-25% and increased glucose utilization by 38-65% in the lateral habenular nucleus; an important relay between striatal/limbic areas and the mid-brain raphe nuclei. The findings emphasize the potential importance of the hippocampus as a site of action for 5-HT1A receptor active drugs in vivo and also suggest that functional activity in the striatal/limbic-habenular-raphe pathway may be influenced by gepirone, ipsapirone and buspirone.

Release of 5-hydroxytryptamine (5-HT) from medullary and mesencephalic raphé neurones after grafting to the rat hippocampus: evidence for regulation by 5-HT1A autoreceptors

The overflow and metabolism of serotonin (5-HT) from transplants of embryonic medullary and mesencephalic raphé neurones in the previously 5-HT-denervated hippocampus have been analyzed in vivo using microdialysis. Output of 5-HT and its metabolite 5-hydroxyindolacetic acid (5-HIAA) from such grafts was as great (medullary) or greater (mesencephalic) than that measured in the normal intact hippocampus. Systemic administration of the putative 5-HT1A receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) led to a 50-80% reduction in 5-HT levels in hippocampal dialysates from both intact and raphé grafted hippocampus. Since 8-OH-DPAT normally reduces 5-HT release from the nerve terminal via activation at the somatodendritic 5-HT1A autoreceptor and subsequent inhibition of impulse flow, the results indicate that 5-HT output from both medullary and mesencephalic raphé grafts can be regulated by autoreceptors and is dependent on serotoninergic neuronal activity.

Effect of short- and long-term administration of lithium on the release of endogenous 5-HT in the hippocampus of the rat in vivo and in vitro

The present study determined the effect of short- (3 days) and long- (21 days) term treatment with lithium on the release of 5-hydroxytryptamine (5-HT) form the hippocampus of the rat, measured both in vivo using microdialysis and in vitro using incubated slices. In the in vivo experiments (on the chloral hydrate-anaesthetized rat) electrical stimulation of the dorsal raphe nucleus for 20 min evoked an increase of 5-HT in dialysates of hippocampus, which both lasted for the duration of the stimulus and was frequency-dependent (2-10 Hz). Electrical stimulation of the dorsal raphe nucleus, at low stimulation pulse frequencies (2 and 3 Hz), released 3-4 fold more 5-HT in rats treated for 3 days with lithium chloride (3 mmol/kg s.c. twice daily), compared to controls. However, the effect of stimulation of the dorsal raphe nucleus was not altered in rats receiving lithium in the diet for 21 days. Basal levels of 5-HT in hippocampal dialysates for rats receiving long- but not short-term treatment with lithium, were significantly lower than controls. In agreement with the in vivo experiments, the in vitro experiments showed that depolarization (high potassium)-evoked release of endogenous 5-HT from slices of hippocampus of rats treated with short- but not long-term administration of lithium was enhanced compared to controls. These experiments provide direct biochemical evidence that short-term treatment with lithium increases depolarization-evoked release of endogenous 5-HT in the hippocampus, an effect which may be related to the rapid antidepressant actions of the drug.(ABSTRACT TRUNCATED AT 250 WORDS)