Search

Depression is one of the most common mental disorders, but its etiology is not completely understood. It is assumed that peptidergic system components are involved in the formation of this pathology. Neuropeptides play an important role in the regulation of mental and emotional states. Сarboxypeptidase E is a key enzyme of peptide processing; it regulates neuropeptide levels in the various structures of the nervous system. We have studied effects of a single dose of reboxetine on the activity of carboxypeptidase E in various brain regions and the adrenal glands of rats. The reboxetine injection decreased carboxypeptidase E activity in the pituitary gland (12 h after injection), in the pituitary gland, the quadrigeminal bodies, the medulla oblongata, the hypothalamus, the hippocampus and the amygdala (24 h after injection), in the pituitary gland and striatum (72 h after injection). The enzyme activity in adrenal glands remained basically unchanged. Apparently, the decrease of carboxypeptidase E activity may influence the level of regulatory peptides involved in the pathogenesis of depression.

Effect of single selank administration on activity of carboxypeptidase H and of phenylmethylsulfonylfluoride-inhibited carboxypeptidase - enzymes detaching arginine and lysine from C-terminus of molecules-precursors of biologically active peptides was studied. The preparation has been shown to cause long, preserved for 24 h changes of activities of these carboxypeptidases. It is suggested that the change in activity of the studied enzymes can be one of mechanisms of regulation of level of neuropeptides at action of selank.

The acid-base parameters and buffer systems of blood of different qualifying groups of sportsmen in physiological condition and at physical work were studied. It is shown that initial differences of the acid-basic condition and buffer capacity of integral blood of sportsmen of high qualifying group lead to changes of the pH dynamics at raising concentration of lactate. Dynamics of the blood lactate concentration is analyzed at stepped-raising exercise in sportsmen of different qualification, the possible molecular mechanism of sharp increase in concentration of lactate in the blood is discussed. It is shown that the point of a break on a curve of change of the pH precedes a point of break on a curve of increase in concentration of lactate at physical work. The received results can be used for definition of the moment of approach of an anaerobic threshold with pH-measurement of the blood.

Essential edema-proteinuria-hypertension (EPH) gestosis still represents an important obstetrical problem. We have investigated the activity of carboxypeptidase H (CPH), phenylmethylsulfonyl fluoride inhibited carboxypeptidase (PMSF-CP), carboxypeptidase M (CPM) and angiotensin-converting enzyme (ACE), the main carboxypeptidases in human placenta under normal conditions and mild EPH-gestosis. Gestosis was accompanied by the decrease in activity of the enzymes involved into metabolism of regulatory peptides (ACE, CPH, PMSF-CP, CPM) compared with their activity in placenta under physiological pregnancy. Correlation analysis revealed positive correlation between placental CPH and CPM (r = 0.2735*) in EPH-gestosis. These findings suggest involvement of placental proteases into formation of compensatory-adaptive reactions in the fetoplacental complex at EPH-gestosis; the data obtained may be also employed for the development of methods of prophylaxis and corrections of metabolic impairments in pathology of pregnancy.

The effect of a single dose administration of arecholine and atropine on the activities of carboxypeptidase H and phenylmethylsulfonyl fluoride-inhibited carboxypeptidase involved into the final stage of formation of biologically active neuropeptides from precursors has been studied. Changes in the enzyme activities were evident during at least 72 h after administration of these drugs. These results suggest that one of possible mechanisms of reduction of neuropeptide levels by arecholine and atropine consists in suppression of activity of enzymes taking part in there metabolism--carboxypeptidase H and phenylmethylsulfonyl fluoride-inhibited carboxypeptidase.

The activity of peptidyl-dipeptidase A and carboxypeptidase N taking part in peptide metabolism in the serum of patients with Alzheimer disease were studied. The role of these enzymes in the metabolism of neuropeptides and beta-amyloid at the Alzheimer disease was discussed.

Effects of dams stress on the carboxypeptidase H: the neuropeptide exchange enzyme in the hypothalamo-pituitary-adrenall-gonadal system, was studied in the litter of different age (0, 14, 28, 45, and 120 day after birth) was studied. The sex differences in dynamic of enzyme activity in intact animals are substantiated. The effect of prenatal stress on carboxypeptidase H activity dependes on age and sex of animals. Prenatal stress is altering during the age dynamics of enzyme activity. This in the pituitary gland and hypothalamus of prenatal stressed female rats was a control for the male rats. In the adrenal and gonadal gland of prenatal stressed males, this was a control for the female rats female. The role of carboxypeptidase H in pubescence and mechanisms of effect of prenatal stress on sex system functional are discussed.

Consumption of dams ethanol increased the posterity locomotion activity in open field test. The increase in female rats was higher then in male ones. Differences in the carboxypeptidase H and PMSF-inhibited carboxypeptidase activities between the brain regions and adrenal medulla of prenatally exposed to ethanol and intact rats were found. The changing of enzyme activities in female rats was higher then in male ones. It is possible that dams ethanol consumption induced profound changes in locomotion mediated, at least partially, by changes in the rate of proteolytic processing of neuropeptide precursors.

The effect of a single atropine administration on the activities of angiotensin-converting enzyme and carboxypeptidase N taking part in peptides metabolism was studied. Changes in the enzymes activities after administration were evident during at least 72 h. The role of these enzymes in the metabolism of neuropeptides under the effect of atropine was discussed.

Effect of a single emotional-algesic stress on the carboxypeptidase H and PMSF-inhibited carboxypeptidase activities (phenylmethylsulphonilfluoride-inhibited carboxypeptidase) taking part in the final stage of formation of biologically active neuropeptides from precursors, was studied. Activity of the enzymes depended on duration of the stress and time after the stress in pituitary and adrenal glands. Differences in changes of carboxypeptidase H and PMSF-inhibited carboxypeptidase activities was found, especially in adrenals. The role of enzymes in emotional-algesic stress development and in metabolism of regulatory peptides by the stress was discussed.

It is revealed, that the activity of neuropeptide metabolism enzymes (carboxypeptidase H, phenylmethylsulfonilfluorid-inhibited carboxypeptidase) in the female rat tissues depends upon the stage of estrus cycle. The carboxypeptidase H activity in the pituitary gland is the highest in proestrus; it is almost 3 times higher in comparison with diestrus; it is a little bit higher in striatum on the stage of estrus, than in diestrus and proestrus, in adrenals on the stage of proestrus and estrus it is a little bit lower, than in diestrus; in the ovaries on the stage of proestrus it is much higher, than in estrus and diestrus. The activity of PMSF-inhibited carboxypeptidase in ovaries on the stage of proestrus and diestrus is 1.7-1.8 times higher, than at the stage of diestrus. The activity of carboxypeptidase M in adrenal tissue at the stage of proestrus is 35-40% of that at the stage of diestrus and estrus. The activity of carboxypeptidase M in the ovaries at the stage of diestrus is 45-50% of that at the stage of diestrus and estrus. The role of the investigated enzymes in cyclic changes of a level of biologically active peptides and in regulation of estrus cycle is discussed.

It was found that testosterone propionate (3 mg/kg of body weight) and progesterone (1 mg/kg of body weight) partially prevent an augmentation of the carboxypeptidase H activity in the mouse pituitary gland under stress caused by a single intraperitoneal administration of olive oil. In testicles, testosterone prevented augmentation of the enzyme activity within 0.5 hours but increased it through in 4 and 24 hours after treatment. Progesterone in testicles augmented the enzyme activity within 0.5 hours, but not in 4 and 24 hours. Sex steroids were not affected by stressinduced carboxypeptidase H activity in hypothalamus and adrenal medulla. It was concluded that carboxypeptidase H did not take part in integration of hypothalamus-pituitary-adrenal and hypothalamus-pituitary-gonadal axis under the stress.

It is discovered that chronic consumption of ethanol induced decrease of carboxypeptidase H activity in striatum by 27%; increase of carboxypeptidase M activity in hippocampus by 67% and decrease in cerebral hemispheres by 34%; phenylmethylsulfonyl fluoride-inhibited carboxypeptidase activity increase in hypothalamus by 141%, in striatum by 60% and in optic and lamina quadrigemina by 34%. The role of basic carboxypeptidases in mechanisms of ethanol influence on the peptidergic systems are discussed.

It is discovered that chloroform narcosis does not influence on carboxypeptidase H and phenylmethylsulfonyl fluoride-inhibited carboxypeptidase activity in the rats hypothalamic-pituitary-adrenal axis. Ether narcosis provokes an increase of PMSF-inhibited carboxypeptidase activity in the pituitary body approximately in 8 times and carboxypeptidase H activity in hypothalamus by 29 percents in comparison with the intact animals. It is supposed that at research neuropeptides and their metabolism enzymes and especially the answer to a stress chloroform narcosis would be the better anaesthesia method than ether narcosis.

Modificated method for the determination of the angiotensin converting enzyme (EC 3.4.15.1) activity in neural tissue is proposed. The methods is based on fluorimetrically determination of released dansyl-Phe from dansyl-Phe-Ala-Arg at pH 7.6. Km is 50 +/- 10 MM. The high specificity of the method is provide by using captopril, the high specific angiotensin converting enzyme inhibitor. The sensitivity of the method is 0.001 nmol/min per mg protein that it is lesser in 15-fold than the lowest enzyme activity in brain region. The distribution of the angiotensin converting enzyme activity that using the method in brain regions and peripherial tissues of rat is presented.

Testosterone propionate decreased activity of carboxypeptidase H in the male mongrel mice pituitary gland, activity of the CP H in testicles, and increased these parameters in 4 hours after treatment. Progesterone decreased the CP H activity in pituitary gland and increased it in testicles. Progesterone increased the CP H activity in female pituitary gland and decreased it in adrenal gland and hypothalamus. The role of the CP H in the effects of the sex steroids on the function of peptidergic systems is discussed.

Effects of single intraperitoneal administration of testosterone propionate (3 or 30 mg/kg body weight) on activity of carboxypeptidase H in pituitary body and hypothalamus of female white mouse were studied. It was found that testosterone propionate treatment (3 and 30 mg/kg body weight) increased the carboxypeptidase H activity in pituitary through 0.5 hour and it decreased one in 24 hours after treatment. The carboxypeptidase H activity in hypothalamus was lower as compared with control animals in 24 hours after testosterone propionate treatment in the dose 3 mg/kg body weight. However, the carboxypeptidase H activity in hypothalamus was lower in 0.5 and 24 hours and it was higher in 4 h after testosterone propionate treatment in the dose 30 mg/kg body weight as compared with the control. These data suggest that testosterone affects the carboxypeptidase H activity by changing the level of enzyme gene expression.

The peculiarities of metabolism of enkephalins at different functional conditions of the organism, different pathology and at the influence of some extreme factors are considered. Some special attention is given to the problem of interrelation and interdependence of enkephalins with proteolytic enzymes, participating in their synthesis and degradation. It is concluded that the biological property of neuropeptides as well as their participation in different physiological and pathological conditions of the organism very much depend on the peculiarities of functioning of enzyme systems of metabolism of neuropeptides.

It is revealed, that analogue of the gamma-aminobutyric acid--sodium hydroxybutyrate causes decrease of activities carboxypeptidase H and angiotensin converting enzyme in pituitary gland, hypothalamus and striatum. The most expressed changes of enzyme activities were observed in pituitary gland and hypothalamus. The activity of carboxypeptidase H changes more essentially, than one of angiotensin converting enzyme. The assumption one of mechanisms of influence the hydroxybutyric acid and, possible, the gamma-aminobutyric acid, on neuropeptides level is changes of activity of enzyme of biologically active peptides exchange is expressed.

The structure, physical, chemical and catalitical properties, functions and biological role of mammalian basic carboxypeptidases are observing. On the strength of the genetic and filogenic research data it is supposed the existence of a family of basic metal-dependent carboxypeptidases and the plan of it evolution is proposed. The connections between structure, localisation and function of this enzyme are discussed.

Questions on the molecular forms multiplicity, certain physical, chemical and catalytical properties, the mechanisms of the activity regulation and biological role of the angiotensin-converting enzyme have been considered. Special attention was paid to the consideration of the angiotensin-converting enzyme role in brain regulative neuropeptide metabolism.

The activity of carboxypeptidase (CP) H, the enzyme taking part in neuropeptide formation, and activity of recently described phenylmethylsulfonyl fluoride (PMSF)--inhibiting CP in males and females of white mongrel rats were studied. Minor differences between the CPH activities in brain regions were found in hippocampus. PMSF-inhibited activity of carboxypeptidase was significantly higher in females than in males in pituitary gland, adrenal gland, olfactory bulbus, optic and auditory bills, cerebellum, hippocampus, striatum, cerebral hemispheres and spleen. The CPH activity was 5-fold higher in ovaries than in testicles. PMSF-inhibited CP activity in testicles was 3.7-fold lower than in ovaries. Possible participation of basic CP in determination of sexual differences of some neuropeptide level and protein catabolism is studied.

Phenylmethylsulfonyl fluoride (PMSF)-inhibited carboxypeptidase (CP) is recently described exopeptidase, that cleaved arginine residues from C-terminal of enkephalin synthetic analogs. The highest enzyme activity was found in the adrenal gland and 40% lower one was revealed in the pituitary gland. A 2.5-fold lower than PMSF-inhibited CP activity in adrenal glands was present in testes. The enzyme activity in the brain regions, liver and spleen was about 2.3-fold lower than in the pituitary gland. Its activity in kidneys is insignificant. In the brain region the lowest PMSF-inhibited CP activity was observed in hippocamp and optic and auditory hills, the highest enzyme activity, in the olfactory bulbus and cerebral hemispheres. The differences between brain regions with the highest and the lowest PMSF-inhibited CP activity do not exceed 1.5 fold. The tissue and regional distribution of PMSF-inhibited CP correlated with that for CPH, enzyme of regulatory peptides processing, and it did not correlate with the distribution of lysosomal CPB. The results allow one to suggest the involvement of PMSF-inhibited CP in the processing of the precursors of biological active peptides and secretory proteins. The differences of distribution of PMSF-inhibited CP and CPH are probably connected with involvements of these enzymes in the processing of precursors of different regulatory peptides.

The activity of the PMSF-inhibited carboxypeptidase in different tissues and brain regions of Erinaceus europaeus has been studied. The highest PMSF-inhibited carboxypeptidase activity, has been discovered in the pituitary gland and in some peripheral tissues: tests, lung, kidney, adrenal gland, spleen. The PMSF-inhibited carboxypeptidase activity in the brain regions is approximately two folds as low in the peripheral tissues. The activity of PMSF-inhibited carboxypeptidase in the brain regions also is 3-4 fold as low as that in the pituitary gland. The PMSF-inhibited carboxypeptidase activity in brain regions rich for the neuron bodies is higher than that in the conduction paths. In skeletal muscle and in blood serum the PMSF-inhibited carboxypeptidase activity has not been found.

Activities of basic carboxypeptidases (CP) in rat brain regions and peripheral tissues were determined on postnatal days 0-90. The highest phenylmethylsulfonyl fluoride-inhibited activity was detected immediately after birth; activity decreases on day 10 with subsequent increase on day 20 and decrease on day 90. The CPE activity was the lowest immediately after birth, increased on day 30, and decreased on day 90. The lysosomal CPB activity was highest at birth and on day 90 and was the lowest on day 20. The activity of CPN slowly increases till day 20 and then it decreases. The relationship between dynamics of basic CP activity in ontogenesis and functional role of these enzymes is discussed.

The subcellular localization and properties of enzymes involved in processing of neuropeptide precursors and in inactivation of active peptide forms are considered. It is concluded that the role of proteolytic enzymes in neuropeptide metabolism is determined by their subcellular localization and substrate specificity.

There was discovered a resemblance in the influence of some pharmacological agents such as ethanol, diazepam and rezerpine on the activity of enzymes of metabolism of biological active peptides in the blood under emotional stress. It was determined that the character of the influence depends on the emotional status of animals. The possibility of drawing both angiotensin converting enzyme and carboxypeptidase N in the stress-protection action of the ethanol, diazepam and rezerpine is discussed.

Captopril was investigated for its effects on the activity of angiotensin-converting enzyme in the rat blood serum, pituitary, hypothalamus, and striatum, as well as for those on the animals, behavior in the open-field test. During its single administration the agent was found to lower the activity of angiotensin-converting enzyme in all the examined brain regions and serum. During chronic administration captopril decreased the mobility of the animals in the open-field test, diminished, the activity of the enzyme in the hypothalamus and striatum and enhanced it in the pituitary and serum. It is suggested that the effect of captopril might be due to imbalance in the changes of angiotensin-converting enzyme activity in various brain regions of the rats.

The review summarizes contemporary views on the biological role, levels and mechanisms of regulation of carboxypeptidase H--the exopeptidase of secretory vesicles removing arginine and lysine residues from C-termini of peptides. It is concluded that although carboxypeptidase participates at the terminal stages of biological active peptide generation, it does not determine the levels of active neuropeptides in the organism.

Inhibition of soluble and membrane-bound carboxypeptidase H in rat hypothalamus, striatum and pituitary gland by hydrocortisone and dexamethasone treatment in vivo has been established. Differences in the dynamics of change in the activity were determined by the action of hydrocortisone and dexamethasone. Differences of the dynamics of change in soluble and membrane-bound carboxypeptidase H activity were also observed. Possible causes of these differences are discussed.

Cat brain carboxypeptidase releasing C-terminal arginine from the synthetic substrate, dansyl-Phe-Leu-Arg, was partially characterized. The enzyme has a molecular weight of 100-120 kDa, displays the maximal activity at pH 6.0-6.5 and is strongly inhibited by phenylmethanesulfonylfluoride and 4-chloromercuribenzoate, less strongly (by 40%) by iodoacetamide and is not inhibited by N-ethylmaleimide, 2-mercaptoethanol, EDTA, Co2+ and guanidinoethylmercaptosuccinic acid. The Km values for the hydrolysis of dansyl-Phe-Leu-Arg and dansyl-Phe-Ala-Arg by soluble carboxypeptidase are 48 and 96 microM, respectively. By all properties, this carboxypeptidase differs from other known carboxypeptidases. Possible participation of the enzyme in neuropeptide metabolism is discussed.

Chronic consumption of the highly specific angiotension-converting enzyme inhibitor captopril was found to decrease the activity of the enzyme in the rat hypothalamus and striatum and to enhance it in the pituitary and blood serum. The agent also increased the activity of carboxypeptidase N in the serum and that of carboxypeptidase H in the pituitary. Reserpine, a catecholaminergic blocking agent, reduces the pituitary and serum activities of angiotensin-converting enzyme and activates soluble carboxypeptidase H in the pituitary and striatum and membrane-bound carboxypeptidase in the hypothalamus and striatum. Possible mechanisms of action of captopril and reserpine on the activity of the enzymes in question, as well as a contribution of these enzymes to their antihypertensive effect are discussed in the paper.

The activity of carboxypeptidase H involved in metabolism of neuropeptides was studied in rats resistant and predisposed to emotional stress under normal and stress conditions. The enzymatic activity was higher in the striatum and hypothalamus of the rats predisposed to stress than that of stress-resistant animals. Emotional stress resulted in activation of the enzyme in these both groups of animals, while the dynamics of the enzyme activity depended on the resistance of animals to stress and the poststress interval. There was a correlation between the activity of carboxypeptidase H and the content of neuropeptides in animals with varying stress-resistance.

Carboxypeptidase H activity in the brain of rats with different resistance to emotional stress was shown to change differently. The enzyme activity during stress in hypophysis was higher in predisposed rats but in striatum and hypothalamus it was lower in the animals stable to the stress. The activity of soluble and membrane bound enzyme in hypophysis during the emotional stress was changed in different direction but in striatum and hypothalamus the activity of both forms of the enzyme was changed equally. The activity of a soluble form was changed larger than in membrane-bound one. Differences of functions of soluble and membrane-bound forms and their participation in emotional stress development in rats with different tolerance to stress are discussed.

Inhibition of the angiotensin-converting enzyme by guanidino-ethylmercaptosuccinic acid, a highly specific inhibitor of carboxypeptidase H, and inhibition of carboxypeptidase H by captopril, a highly specific inhibitor of the angiotensin-converting enzyme, in vivo were studied. Guanidinoethylmercaptosuccinic acid and captopril had no effect either on the angiotensin-converting enzyme or the carboxypeptidase H activities in vitro. The putative mechanisms of the inhibitors effects of the enzyme activity are discussed.

Diazepam increased the carboxypeptidase H activity and decreased the angiotensin converting enzyme activity in the rat brain. Joint action of diazepam and emotional stress changed the carboxypeptidase H activity to the least extent and the angiotensin converting enzyme activity to the utmost extent as compared to the agents' separate effects. The role of both enzymes in the diazepam effect is discussed.

Angiotensin converting enzyme activity in hypophysis and S. grisea of the stable rats was higher but in hypothalamus it was lower than in the predisposed ones. Activity of the enzyme depended on the area, degree of tolerance to stress and a kind of stress. The role of angiotensin converting enzyme at the determination of tolerance to emotional stress and stress development was discussed.

The carboxypeptidase N and angiotensin converting enzyme contents was 1.4-1.5-fold higher in emotionally stable rats as compared with those predisposed to an emotional stress. Possible causes of this phenomenon are discussed.

Activity of carboxypeptidase N [correction of H] increased under emotional-algic stress in the rat pituitary gland and hypothalamus. Carboxypeptidase N [correction of H] seems to be involved in development of the stress response, and soluble forms of the enzyme take part in processing of secretory peptides. Membrane-bound forms take part in processing of the neuropeptides specific by their central action.

The effect of emotional stress on both carboxypeptidase N and angiotensin converting enzyme activities in the blood serum of stable and predisposed rat was studied. It was found that activities of both enzymes in serum of stable rat was higher as compared with those predisposed to emotional stress. During emotional stress a decrease of both enzymes activities was observed. Both enzymes activities in rats with different degrees of tolerance to emotional stress were changed differently.

Physico-chemical and catalytic properties of opioid peptides metabolism enzymes are considered. Methods for determination of their activity are analyzed.

The activity of carboxypeptidase H was inhibited dissimilarly in some brain regions of rats after combined effects of ethanol and immobilization stress. This dissimilar effect of ethanol and stress on activity of soluble and membrane-bound carboxypeptidases was detected in the midbrain, hippocamp, and striatum. The role of carboxypeptidase H in the stress-protective effect of ethanol is discussed.