We found previously that combined administration of imipramine, citalopram and, to a lesser extent, mianserin with MK-801, a non-competitive NMDA receptor antagonist, reduced the immobility time in the forced swimming test in rats more potently than administration of the antidepressant or MK-801 alone. In present paper we examined the effect of other antidepressants in this model. (+)-Oxaprotiline and (-)-oxaprotiline which, when given alone, showed a weak positive effect, increased the action of MK-801. Fluoxetine, inactive when given alone, markedly increased the effect of MK-801. Moreover, the positive effect after combined treatment was found in the experiments in which antidepressants and MK-801 given separately were inactive. A reduction in the immobility time was also observed in those experimental paradigms in which the locomotor activity was not increased. The effects of combined treatment with the antidepressants studied + MK-801 were antagonized by haloperidol, but not by prazosin. The obtained results indicate that mainly a dopamine mechanism seems to be involved in the synergistic action of MK-801 and the antidepressants in the forced swimming test.
The effect of a steric hindrance around the protonation center of the model 4-substituted 1-(3-chlorophenyl)-piperazines 1-9 and 11-14 on their affinity for 5-HT1A and 5-HT2 receptor sites was investigated. Additional evidence for hydrophobic interactions between the N-4 hydrocarbon substituents and 5-HT1A receptors has been presented. However, the hydrophobic forces play a minor role in stabilization of the bioactive complex with 5-HT2 receptors. It has also been found that even bulky substituents around the protonation center of 1-aryl-piperazines are well tolerated at both 5-HT1A and 5-HT2 sites.
In 2K,1C-RHR (two-kidney, one-clip hypertensive rats) serotonergic mechanisms in blood platelets were studied. The endogenous serotonin (5-HT) concentration in whole blood and in platelets remained unchanged in relation to the sham operated rats. Also the uptake of labelled 5-HT in rats with renal hypertension was not altered. However platelets aggregability was increased in 2K,1C-RHR. Acute administration of captopril (10 mg/kg and 100 mg/kg po) diminished blood pressure but did not change either the concentration of 5-HT in whole blood and in platelets of hypertensive rats or the uptake of this amine. Platelets aggregation and the amplifying effect of 5-HT in hypertensive rats were also unchanged after acute captopril administration. Similar results were observed after its administration in a dose of 30 mg/kg for one week. Our results indicate that captopril did not affect the platelets serotonergic mechanisms in 2K,1C-RHR.
Esters of N,N-diethylaminoacetic acid and hydroxyamines, obtained from structurally different natural monoterpenes, were pharmacologically examined. It was proved that salts of the obtained compounds had local anesthetic properties in infiltration anesthesia, compounds 9, 6 and 8 having been more potent than lidocaine. Compounds 7-9 slightly increased the arrhythmogenic dose, and compound 12 - the lethal dose of strophanthin. All the examined compounds transiently decreased the arterial blood pressure and displayed a cardiopressive activity.
A simple, rapid and sensitive high-performance liquid chromatographic method for the simultaneous determination of propafenone and 5-hydroxypropafenone in human serum is described. Method involves a single-step extraction of the drug and its metabolite with dichloromethane:2-propanol (4:1 v/v) mixture from 0.2 ml of serum. Separation of the investigated compounds on deactivated Supelcosil LC18-DB column is accomplished by ultraviolet detection at 210 nm. The limit of detection is 10 ng/ml for propafenone and 4 ng/ml for 5-hydroxypropafenone. The method is useful for the routine monitoring of propafenone and its main metabolite in serum as well as for the pharmacokinetic studies.
High affinity binding sites for adenosine were identified in rat kidney cortex basolateral membranes. Kinetic analysis indicates two sets of [3H]adenosine, [3H]ADO, binding sites, one with high affinity and Kd = 0.84 +/- 0.25 microM, one with low affinity and Kd = 4.74 +/- 0.37 microM. The ADO receptors were further characterized using ADO analogs as binding inhibitors. The most potent inhibitor of [3H]ADO binding was N-methyl-adenosine with a Kd of 5 microM, whereas 2-deoxyadenosine was about 50 times less potent. The binding of [3H]phenylisopropyladenosine, [3H]PIA, and [3H]-N-ethylcarboxamidoadenosine, [3H]NECA, to basolateral membranes was rapid and reversible. The Scatchard plot of [3H]PIA binding showed monophasic curves for experiments performed at 0 degrees C and 37 degrees C. The apparent Kd of [3H]PIA binding at 0 degrees C was 0.19 +/- 0.05 nM and 0.34 +/- 0.07 nM at 37 degrees C. The binding of [3H]NECA to basolateral membranes was found with an apparent affinity Kd of 110 +/- 50 nM at 0 degrees C. Pretreatment of membranes with N-ethylmaleimide (NEM) inhibited the [3H]PIA binding and did not affect the [3H]NECA binding. These results demonstrate that both A1 and A2 adenosine receptors are present in basolatertal membranes of rat kidney.
The antiarrhythmic action of diltiazem in the model of barium arrhythmia was studied in rats non-dependent and dependent on ethanol. The results of our studies showed that single intragastric administration of ethanol jointly with diltiazem did not significantly attenuate the antiarrhythmic effect of diltiazem. Ethanol administered repeatedly and jointly with diltiazem influenced the antiarrhythmic action of diltiazem in different ways, depending on the used dose of diltiazem. After repeated joint administration of ethanol and diltiazem in a lower dose, attenuation of the antiarrhythmic effect of diltiazem was not observed. Repeated joint administration of ethanol and diltiazem in a higher dose attenuated the antiarrhythmic effect of diltiazem. Those experiments also showed that single administration of diltiazem did not significantly influence the ethanol level in the blood; however, when administered repeatedly, diltiazem reduced the concentration of ethanol in blood.
2,4-Disubstituted 5-amino-6-pyrimidinecarboxylic acid derivatives 5-13 were synthesized and evaluated for their pharmacological activity. Compounds 5, 7, 9, 10 and 12 showed antiaggressive effect, compounds 6 and 10 showed synergism with hexobarbital while compound 6 exerted analgesic activity.
There has long been acceptance within healthcare that one of the roles that nurses fulfil is to do with patient advocacy. This has historically been positioned as part of the philosophical and inherent requirements of the nursing profession at large and is supported through shared conceptualisations of the nursing profession. Such conceptualisations are communicated to nursing professionals by way of first their education, and second their professional codes, guidelines and standards for practice. The focus on advocacy is further embedded within patient-centred care frameworks and concepts of the nurse-patient therapeutic relationship. Nurses have also been considered ideally placed to undertake the work of patient advocacy due to the 24/7 nature and intimacy of the care provided. What this means is that nurses are under the impression that that they must be an advocate for their patients through their nursing practice. However, for a fundamental concept of nursing, advocacy is poorly defined, and practices commonly associated with advocacy are undercut by the professionalisation of nursing and other constraints. In addition, nursing standards and frameworks of care are being actively reframed around ideas of empowerment which do not necessarily fit well with those of advocacy. This article thus suggests that it is time to recognise that the work of advocacy is no longer representative of what nurses (can) do in practice, and to explicitly reorient conceptualisations of nurse practice around empowerment. This article will further analyse what this may look like in practice.
Peptide YY (PYY) is a recently discovered polypeptide which has been proposed as physiological inhibitor of pancreatic exocrine secretion. The purpose of this study was to evaluate the effects of exogenous PYY on pancreatic blood flow and oxygen consumption. In anesthetized dogs, the superior pancreatico-duodenal artery blood flow (SPBF), pancreatic microcirculatory blood flow (PBF) and pancreatic oxygen consumption (PVO2) were determined. Control values for SPBF, PVO2 and PBF averaged 43.3 ml/min, 1.8 ml/min, and 57.5 ml/min/100g of tissue, respectively. Following iv injection of PYY at doses of 200 and 400 pmol/kg the values of SPBF decreased by 12 +/- 1% and 22 +/- 2%, respectively. PVO2 was reduced by those doses of PYY by 9 +/- 1 and 17 +/- 3%, respectively. PBF was also reduced by 16 +/- 2 and 34 +/- 2%, respectively after those doses of PYY. Pretreatment with phentolamine reversed the blood flow and PVO2 responses to PYY because SPBF, PVO2 and PBF were significantly increased above the control level. However, after additional pretreatment with propranolol the pancreatic vascular and metabolic responses to PYY were abolished. The above pancreatic responses to PYY were also significantly reduced after acute adrenalectomy. The experimental data indicate that adrenergic pathway is involved in the mechanism of action of PYY on the pancreatic circulation.
To investigate a possible functional interaction between 5-HT1B and 5-HT1A or 5-HT2 receptors we studied the effects of 5-HT1A selective agonists 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) and gepirone, of a 5-HT1A/5-HT2 agonist 5-methoxy-N,N-dimethyltryptamine (5-MeODMT) and of a putative 5-HT2 agonist (+/-)1-(2,5-dimethoxy-4-iodophenyl)-2-amino-propane (+/- DOI) on the 5-HT1B receptor-mediated hypothermia induced by m-trifluoromethylphenylpiperazine (TFMPP) (25 mg/kg) or m-chlorophenylpiperazine (m-CPP) (20 mg/kg) in mice. 8-OH-DPAT (1.25-5 mg/kg), gepirone (1.25-5 mg/kg), 5-MeODMT (2-8 mg/kg) and (+/-)DOI (0.5-2 mg/kg) reduced dose-dependently the TFMPP- or m-CPP-induced hypothermia. At the same time 8-OH-DPAT (2.5 and 5 mg/kg, but not 1.25 mg/kg) and gepirone (1.25-5 mg/kg) themselves decreased the body temperature in mice, while 5-MeODMT (2-8 mg/kg) and (+/-)DOI (0.5-2 mg/kg) did not affect it. The present results suggest that a functional interaction exists between 5-HT1B and 5-HT1A or 5-HT2 receptors.
The effect of six 5-HT3 receptor antagonists: ondansetron (0.01-3 mg/kg ip), granisetron (0.01-1 mg/kg ip), zacopride (0.01-3 mg/kg ip), tropisetron (0.001-0.1 mg/kg ip), MDL 72222 (0.01-3 mg/kg ip) and DAU 6215 (0.01-3 mg/kg sc) were examined in the conflict drinking test (Vogel test) and in the elevated plus-maze test in rats. Ondansetron (0.1-0.3 or 1 mg/kg), zacopride (0.1-1 mg/kg) and tropisetron (0.01 mg/kg) increased the punished responding in the Vogel test and showed anxiolytic effects in the elevated plus-maze test. Their effects were limited to a narrow dose range and were not dose-dependent. Granisetron (0.1 mg/kg) exhibited an anti-conflict activity, but was ineffective in the elevated plus-maze test. MDL 72222 and DAU 6215 were ineffective in both those tests. On the other hand, diazepam (2.5-10 mg/kg), used as a reference drug, was active in either procedure and its effects were dose-dependent. These results indicate that an anxiolytic-like activity is not a common characteristic of 5-HT3 receptor antagonists. Moreover, even the anxiolytic action of drugs which were active in the experimental models used should be accepted with caution.
The effects of C-terminal unsulfated cholecystokinin octapeptide (CCK-8US) and its fragments C-terminal heptapeptide (CCK-7), C-terminal hexapeptide (CCK-6) and C-terminal pentapeptide (CCK-5) were studied on the arterial blood pressure and the isolated rat heart. CCK-8US had only slight hypertensive and no cardiac effects. CCK-5, CCK-6 and CCK-7 had no effect on the arterial blood pressure, the cardiac contraction amplitude and the heart rate. Only CCK-7 increased coronary outflow of the isolated rat heart. CCK-8US and C-terminal fragments; CCK-7 have little effect on the circulation of the rat.
The effect of post-footshock injections of serotonergic agonists into the nucleus accumbens on formation of the open field deficit, has been studied in rats. It was found that the deficient open field behavior, examined 24 h after learned helplessness training, was not modified by local injection of serotonin, buspirone, ipsapirone and ICS 205 930, as well as by peripherally administered citalopram. It is concluded that accumbens serotonin system does not seem to contribute to the balance in the activity of local dopaminergic and GABAergic neurotransmitter mechanisms, previously shown to mediate some behavioral effects of stressors.
The hypoxic radiosensitizer 1-(2-hydroxy-3-methoxypropyl)-2-chloro-4-nitroimidazole [P40] was investigated for its mutagenic activity in bacterial Ames test as well as for genotoxic activity in micronucleus assay in vivo. This nitroimidazole showed the weak mutagenicity towards TA100 strain (base pair substitution) and towards TA98 strain (frameshift) only in the highest concentration. P40 induced also a significant increase in the frequency of micronucleated polychromatic erythrocytes (PCEs) at the doses of 0.6 mg/g and 1.2 mg/g. The maximum time response was at 48 h. The decrease of percentage of PCEs suggested the possible cytotoxicity on bone marrow cells after treatment with P40. Positive results in this battery short-term tests provide evidence of clastogenic activity of P40.
Six new 5(1H)oxo-2,3-dihydroimidazo[1,2-a]pyrimidine-6-carboxylic ethyl esters bearing an aromatic substituent in position 1 or 2 were obtained. Pharmacological studies on the central action of these derivatives were carried out on mice and rats. The highest activity showed compounds 1 and 2 which produced analgesic effects in mice.
The effects of MK-801, a non-competitive NMDA receptor antagonist, and of antidepressant drugs were studied in the forced swimming test in rats. MK-801 reduced immobility time. Combined treatment with MK-801 + imipramine induced a stronger effect in Porsolt's test than administration of either drug alone. Citalopram was inactive when given alone but it potentiated the antidepressant-like effect of MK-801. Haloperidol and prazosin antagonized the effect induced by MK-801 + IMI or CIT. Mianserin interacted with MK-801 in a similar way but to a lesser extent. Its effect was antagonized by haloperidol but not by prazosin. The reduction of the immobility time was also observed in those experimental paradigms in which the locomotor activity was not increased. The results indicate that synergism may exist between antidepressants and MK-801.
The effects of thiophosphoric acid alkaloid derivatives from Chelidonium majus L. (Ukrain, UKSR-222) on the central nervous system (CNS) of mice and rats was studied. Intraperitoneal (ip) administration of Ukrain in doses of 9.5 and 19 mg/kg for mice depressed spontaneous motor activity, decreased body temperature and potentiated the action of hexobarbital. Only in a dose of 19 mg/kg Ukrain produced analgesic action in the hot plate test. It had no protective effect against electroshock or pentetrazol-induced seizures. In rats, ip administration of Ukrain in dose of 14 and 28 mg/kg potentiated the action of amphetamine and apomorphine but had no effect on catalepsy induced by haloperidol. Ukrain used in dose 9.5, 14, 19 and 28 mg/kg antagonized the head twitches induced by 5-HTP and hyperthermia-induced by m-CPP. Biochemical studies indicated that Ukrain did not affect the NA and DA concentrations in the whole rats' brain and did not affect the 5-HT and 5-HIAA concentrations in the whole brain of rats. These findings demonstrate that the central action of Ukrain involves the stimulation of the dopaminergic system and the inhibition of the serotoninergic system.
The effect of xanthotoxol (8-hydroxypsoralen) on proliferation of TCTC cells in vitro has been studied. Xanthotoxol at concentrations of 5 to 50 micrograms/ml inhibited the growth of cells. In cultures with xanthotoxol, decreased amount of cell protein, mitotic index, and decreased ability to form a colony, were observed. Moreover, xanthotoxol disturbed mitoses elevating the number of mitotic cells in the telophase stage. An increase of giant and multinuclear cells was also found. On the basis of these results it can be concluded, that 8-hydroxypsoralen which in comparison with other psoralens is not sensitive to photostimulation, inhibits the cell proliferation anyway. This fact shows that the mechanism of the psoralens activity is to some extent independent from the photostimulation.
Numerous experimental data obtained in the studies of factors influencing the transfer of model drugs (diazepam, inulin, hippurate) into the lymphatic system were evaluated using compartmental pharmacokinetic analysis. The selection of kinetic equations for lymphatic data analysis in respect to blood ones is specific. Lymphatic kinetic equations correspond in every case tested with those used generally in blood kinetic analysis of drugs administered perorally. The lag time parameter is useful in this lymphatic analysis, too.
