Importance of environmental context in the development of amphetamine- or apomorphine-induced stereotyped behavior after single and multiple doses

The present study was designed to determine whether single and repeated pretreatment regimens with amphetamine or apomorphine differ in the context-dependency of sensitization of stereotyped behavior. Male CF-1 mice that were pretreated with a single high dose of amphetamine (14 mg/kg intraperitoneally [IP]) or apomorphine (40 mg/kg subcutaneously [SC]) only became sensitized to a lower test dose of amphetamine (7 mg/kg IP) or apomorphine (3 mg/kg SC) when placed in an environment that was the same as the pretreatment environment. However, animals pretreated with 3 high doses (24-h apart) of amphetamine (14 mg/kg IP) or apomorphine (40 mg/kg SC) did demonstrate sensitization to a lower test dose of amphetamine (7 mg/kg IP) or apomorphine (3 mg/kg SC) when placed in an environment that was different from the pretreatment environment. Context-dependent sensitization, but not context-independent sensitization, was extinguished by pairing the test environment with saline injections instead of drug injections. In addition, it was determined that neither sensitization model could be related to pharmacokinetic factors. Therefore, the results indicate that repeated exposure to amphetamine or apomorphine overcomes the context-dependent component of sensitization of amphetamine- or apomorphine-induced stereotyped behavior.     

Sensitization of apomorphine-induced stereotyped behavior in mice is context dependent

Rationale: The role of the environment in the sensitization of the stereotyped behavioral effects of apomorphine is unclear, since sensitization of this drug effect has either been difficult to demonstrate or has been shown to occur with a low but not a higher dose of apomorphine. Objectives: The present study was designed to determine whether sensitization of the stereotyped behavioral effects induced by a single dose of apomorphine is dependent on environmental context. Methods: CF-1 mice were pretreated with apomorphine or vehicle under different environmental conditions and tested for stereotyped behavior after apomorphine challenge. Animals were scored positively for stereotyped behavior if they remained stationary and exhibited repetitive head and/or fore-limb movements, and data are reported as the percentage of mice rated as positive for stereotyped behavior. Results: When mice were pretreated with 40 mg/kg apomorphine and later tested in the same environment, the dose–response curve for stereotyped behavior elicited by apomorphine was shifted threefold to the left 48 h after pretreatment, and this sensitization persisted for at least 28 days after pretreatment. Mice pretreated with apomorphine did not have higher brain levels of apomorphine after administration of the test dose of apomorphine. When the pretreatment environment was different from the test environment, mice did not exhibit sensitization to apomorphine. Conclusions: These results show that pre-exposure to a single high dose of apomorphine induces a long-lasting sensitization of apomorphine-induced stereotyped behavior that is context dependent. Since apomorphine directly activates dopamine receptors, these observations suggest that a mechanism located postsynaptic to dopamine neurons may be responsible for sensitization of stereotyped behavior. Received: 12 November 1998 / Final version: 14 April 1999     

Acute increases by p-chlorophenylalanine of apomorphine-induced stereotyped behavior in the rat

The stereotyped behavioral syndrome induced in the rat by apomorphine was enhanced by acute systemic administration of PCPA. This effect was dependent on the dose of PCPA and half-maximal at approximately 150 mg/kg, i.p.; it occurred within 30 min, was greatest between 1 and 5 h and had nearly disappeared by 24 h after an acute dose of PCPA. A similar effect was not found at 24 or 48 h following 3 repeated doses of PCPA of 300 mg/kg/day. This effect of PCPA was not reversed by 5-HTP or by high doses of a decarboxylase inhibitor. PCPA alone did not produce stereotyped behavior, although it produced some behavioral excitation in high doses following inhibition of monoamine oxidase. This acute behavioral effect of PCPA to potentiate apomorphine-induced stereotyped responses is unexplained. It does not seem to be due to depletion of 5-HT or to the formation of an amine as an active metabolite. We suggest that PCPA can have behavioral excitatory actions independent of its 5-HT-depleting action.Abbreviations CNS (central nervous system) - Dopa (dihydroxyphenylalanine) - 5-HT (5-hydroxytryptamine, serotonin) - 5-HTP (l-5-hydroxytryptophan) - PCPA ([±]-p-chlorophenylalanine methyl ester·HCl) Supported in part by U.S. Public Health Service (NIMH) Grants MH-16674 and MH-25515, and Research Career Scientist Award MH-74370 (Dr. Baldessarini); and an award from the Scottish Rite Schizophrenia Research Foundation, Supreme Council 33°AA, Scottish Rite, Northern Masonic Jurisdiction of the U.S.A.     

Hypokalaemia in healthy volunteers after single and multiple doses of formoterol or salbutamol

A specific beta(2)-adrenoceptor-mediated effect, hypokalaemia, was studied in healthy volunteers after single as well as multiple dosages of the long-acting agonist formoterol and the short-acting agent salbutamol. The purpose of the study was to test with simple methodologies if rapidly induced tachyphylaxis for this well known systemic effect can be shown and if it will then be more pronounced for the long-acting compound. Hypokalaemia induced by inhalation of, respectively, 72microg formoterol and 1200microg of salbutamol was studied before and after 1 week of medication. Potassium-time curves were described by a biexponential equation and also analysed with a deconvolution technique. Both drugs induced a statistically significant hypokalaemia, the duration of this effect being considerably shorter for salbutamol than for formoterol (p < 0.05 with both methods of analysis). After multiple doses for 1 week, both maximal hypokalaemia and the area under the curve of the hypokalaemic effect had decreased after inhalation of formoterol (p < 0.05) but not after inhalation of salbutamol.It was concluded that plasma potassium as an effect measurement can be used to study in a simple but reproducible way differences of pharmacological interest between various beta(2)-adrenoceptor agonists.     

Effects of penfluridol and other drugs on apomorphine-induced stereotyped behavior in monkeys.

The effects of some drugs on apomorphine-induced stereotyped behavior were studied in male cynomolgus monkeys. Apomorphine produced the dose-dependent stereotyped behavior characterized mainly by continuous licking and biting, and repetitive movements of the hands, head and body in the monkeys. Penfluridol as well as haloperidol showed a clear antagonistic effect on the apomorphine-induced stereotyped behavior, while chlorpromazine was less antagonistic than haloperidol. The antagonistic effect of penfluridol lasted longer than that of haloperidol. Reserpine did not inhibit the apomorphine-induced stereotyped behavior though the drug elicited markedly the behavioral depression and alpha-methyl-p-tyrosine also did not block the stereotyped behavior. Nialamide did not depress the apomorphine-induced stereotyped behavior. In provoking the stereotyped behavior in monkeys, apomorphine probably acts directly on dopamine receptors in the extrapyramidal system, and penfluridol is suggested to act as a dopamine receptor blocker with a long action. The results indicate that protection against apomorphine-induced stereotyped behavior in monkeys may be a useful method for evaluating neuroleptic drugs.     

Pharmacokinetics of co-trimazine after single and multiple doses

Plasma and urinary levels of trimethoprim (TMP), sulfadiazine (SDZ) and N4-acetylsulfadiazine (N4-SDZ) were determined after administration of 1 g co-trimazine (equivalent to 180 mg TMP and 820 mg SDZ) (Kombinax) as a single dose and again once daily for 7 days to 6 normal subjects. Both TMP and SDZ were rapidly absorbed from the gastrointestinal tract with peak plasma levels being achieved within 4 h in all subjects. Elimination half-lives ranged from 8 to 13 h for TMP and from 9 to 15 h for SDZ. Approximately 50% of the administered dose of SDZ was recovered in urine within 24 h of the single dose (32% as unchanged drug and 17% as the N4-acetylmetabolite). For TMP, the urinary recovery during the 24 h following the single dose averaged 39%. Mean plasma levels of TMP, SDZ and N4-SDZ at steady state were moderately higher than those observed after a single dose, but no change in absorption or disposition kinetics of these compounds was seen after repeated dosing.     

Effect of atrial natriuretic peptide on apomorphine-induced stereotyped cage-climbing behavior in mice.

In previous experiments, it was observed that rat atrial natriuretic peptide-(1-28) (ANP-(1-28)) participated in fear-induced learning and memory processes via dopaminergic and cholinergic mediation. Since cage-climbing behavior is described as a simple test for studying dopaminergic activity in the central nervous system, a systemic study was carried out with ANP-(1-28) in order to confirm or to exclude the possible involvement of dopamine in the ANP-induced action in the brain. The present study demonstrate that ANP-(1-28) facilitated cage-climbing behavior in mice in a dose-dependent manner. When combined with apomorphine, the peptide potentiated the effect of the dopamine agonist. The effect of ANP-(1-28) in combination with apomorphine could be antagonized by a selected dose of haloperidol. These data suggest that ANP might be regarded as a dopamine agonist-modulating agent and that a dopaminergic mechanism is a possible mode of action of ANP in the fear-induced learning studied earlier.     

Pharmacokinetics of cefoperazone after single and multiple doses

The pharmacokinetics of cefoperazone was determined following single and multiple intravenous and intramuscular administrations in man. Ten subjects at each dose level were given eleven successive doses, at 12 h intervals of 500 and 1000 mg i.m. and i.v.. Serum concentrations and urinary excretion were determined in all subjects after the first, fifth and eleventh doses. The first i.m. doses yielded mean peak serum levels of 37 micrograms/ml and 76 micrograms/ml at 1.0 h after injection. The first i.v. doses yielded mean serum levels of 93 and 180 micrograms/ml at 5 min after the injection. No tendency toward drug accumulation was observed on multiple dosage. The pharmacokinetics could be described by a linear, open, two-compartment model of drug distribution. The terminal serum half-life (2.1-2.4 h after i.v. doses and 2.6-2.8 h after i.m. doses) remained essentially constant over the period of the study by dose levels. The no-significant differences of areas under the curve between the two routes, at two doses, show the absolute bioavailability of cefoperazone was about 95% following i.m. administration. The high binding to serum proteins (90%) influences favourably the pharmacokinetic parameters of cefoperazone. It yielded high and prolonged serum concentrations and has very useful distribution properties. These favourable properties, together with its good antibacterial activity, suggest that cefoperazone will be effective in treating bacterial infections in human beings.     

Pharmacokinetics of chlorthalidone in the elderly after single and multiple doses

To investigate the discrepancy between the apparent pharmacokinetic disposition of (+)-penicillamine in plasma and urine, the spontaneous degradation of (+)-penicillamine was studied in acidified and non-acidified urine. Degradation was prevented by acidification. The oxidized metabolites were converted to reduced (+)-penicillamine by electrolysis.     

Diltiazem pharmacokinetics in elderly volunteers after single and multiple doses

In young healthy volunteers diltiazem does not have linear kinetics between single and multiple doses. Elimination half-life increases and gives AUC's and Cmax higher than those predicted from single dose data. Kinetics of diltiazem were assessed in 16 healthy elderly after a single 60 mg dose and in 24 healthy elderly after 60 mg every 8 h for 7 days. Thirteen participants completed both studies. Elimination half-life, AUC0-24, AUC0-infinity, and Cmax were (mean +/- SE) 7.4 (1.2) h, 349 (34) ng/ml.h, 392 (44) ng/ml.h, and 43 (5) ng/ml respectively after a single dose. After multiple doses elimination half-life, AUC0-48, AUC0-infinity, Cmax and Cmin were respectively 5.7 (0.3) h, 974 (107) ng/ml.h, 1022 (108) ng/ml.h, 102 (7) ng/ml and 43 (5) ng/ml. Exploratory statistics on the 13 volunteers common to both studies showed that the ratio of AUC desacetyl-diltiazem (DAD)/AUC diltiazem rose between single and multiple doses while elimination half-life of both diltiazem and N-desmethyl-diltiazem (MA), tmax, and AUC MA/AUC diltiazem were not affected. The conclusion of this study is that elimination half-life of diltiazem does not increase in elderly between single and multiple doses, possibly due to an increased biotransformation into DAD.     

Codeine disposition in human hair after single and multiple doses

Objective: We studied the dose-proportion and time-course relationships for the incorporation of codeine into human hair after the administration of three different doses. Subjects: Male volunteers, with dark hair, were given oral codeine either as a single dose of 60 mg (n = 7) or 120 mg (n = 12), or as multiple doses of 30 mg 3 times daily for 5 days (n = 7) (450 mg total dose). Methods: Blood and urine were collected for various times for up to 72 h after dosing. Scalp hair was collected initially by plucking (up to 4 weeks) and later by cutting for up to 10 weeks. Plasma, urine, proximal 1 cm of hair and distal hair were each analyzed for codeine and its metabolites by positive-ion chemical ionization ion trap gas chromatography/mass spectrometry. Results: Codeine was detected in the proximal 1 cm of hair within 30 min of an oral 120-mg dose. Codeine was not detected in the distal hair segment until 3 weeks after receiving a dose of codeine. Codeine was detected in distal hair segments for at least 10 weeks at 30 pg mg^?1 hair following a single 120 mg codeine dose and at 90 pg mg^?1 hair following 30 mg codeine 3 times a day for 5 days. Morphine or the glucuronides of codeine or morphine were not detected in the hair specimens of these subjects. Conclusion: Codeine is rapidly distributed into the germanitive elements of hair in a dose-proportional manner. A portion of the codeine remains bound as the hair grows and can be detected in distal hair for up to 10 weeks after a single dose.     

Diltiazem pharmacokinetics in elderly volunteers after single and multiple doses

In young healthy volunteers diltiazem does not have linear kinetics between single and multiple doses. Elimination half-life increases and gives AUC's and Cmax higher than those predicted from single dose data. Kinetics of diltiazem were assessed in 16 healthy elderly after a single 60 mg dose and in 24 healthy elderly after 60 mg every 8 h for 7 days. Thirteen participants completed both studies. Elimination half-life, AUC0-24, AUC0-infinity, and Cmax were (mean +/- SE) 7.4 (1.2) h, 349 (34) ng/ml.h, 392 (44) ng/ml.h, and 43 (5) ng/ml respectively after a single dose. After multiple doses elimination half-life, AUC0-48, AUC0-infinity, Cmax and Cmin were respectively 5.7 (0.3) h, 974 (107) ng/ml.h, 1022 (108) ng/ml.h, 102 (7) ng/ml and 43 (5) ng/ml. Exploratory statistics on the 13 volunteers common to both studies showed that the ratio of AUC desacetyl-diltiazem (DAD)/AUC diltiazem rose between single and multiple doses while elimination half-life of both diltiazem and N-desmethyl-diltiazem (MA), tmax, and AUC MA/AUC diltiazem were not affected. The conclusion of this study is that elimination half-life of diltiazem does not increase in elderly between single and multiple doses, possibly due to an increased biotransformation into DAD.     

Plasma tenoxicam concentrations after single and multiple oral doses

The pharmacokinetics of single- and multiple-dose administration of tenoxicam 20 mg were evaluated in 8 healthy males. Maximum plasma concentration (Cmax) after the first dose was 2.76 +/- 0.48 micrograms/ml (mean +/- s.d.) and the time to reach Cmax (Tmax) was 5.0 +/- 3.0 h. The area under the plasma concentration-time curve (AUC0-infinity) after a single administration of tenoxicam was 242.5 +/- 73.5 micrograms x h/ml. The elimination half-life (t1/2) was 66.3 +/- 15.8 h and the plasma concentration at 24 hours after dosing (Cmin) was 1.84 +/- 0.33 micrograms/ml. Steady-state plasma concentrations of tenoxicam were virtually reached after 10 consecutive daily doses. At steady-state, Cmax averaged 13.63 +/- 3.33 micrograms/ml and Tmax remained 5.0 +/- 3.0 hours. AUC within a dosing interval at steady-state was 262.2 +/- 67.0 micrograms x h/ml, Cminss was 9.67 +/- 3.25 micrograms/ml, and t1/2 averaged 74.2 +/- 13.3 h. The average fluctuation during multiple-dose administration was 26.8 +/- 8.0% and the accumulation ratio was 5.82 +/- 0.60. Steady-state pharmacokinetic parameters predicted from the first-dose data slightly underestimated observed values, but the results supported the assumption of linear pharmacokinetics during multiple-dose tenoxicam administration.     

注射用法罗培南钠的单剂量和多剂量药代动力学研究

目的考察单次和连续静脉滴注法罗培南钠注射液后健康人体内的药动学过程。方法12名健康受试者随机交叉单剂量静脉滴注给药100,200,300,600mg,单剂量试验结束后进人多剂量试验,8名受试者静脉滴注给药每次200mg,每日3次,连续给药7d,用高效液相色谱法测定血浆和尿中法罗培南的浓度,并采用药动学程序对试验数据进行处理,求算有关药动学参数。结果12名健康受试者单剂量静脉滴注法罗培南注射液后,主要药动学参数Cmax分别为（8．42±1．96）mg／L,（16．64±3．09）mg／L,（24．73±3．58）mg／L,（44．43±3．93）mg／L,T1/2分别为（1．72±0．72）h,（1．60±0．33）h,（1．56±0．21）h,（1．36±0．09）h,AUCOJ分别为（13．90±2．96）mg·h／L,（26．98±5．75）mg·h／L,（38．29±5．29）mg·h／L,（70．58±10．33）mg·h／L,12h累积尿药排泄率分别为31．4％,31．5％,30．5％,34．9％,多次静脉滴注后的主要药动学参数Cmax,T1/2,AUC0-4分别为（15．83±3．96）mg／L、（1．11±0．27）h、（21．93±3．59）mg·h／L,血药浓度波动系数和Gav分别为（5．34±1．30）和（2．74±0．45）mg／L,12h累积尿药排泄率为40．5％。结论单次给药在100～600mg剂量范围内法罗培南呈线性消除,性别对法罗培南的药代动力学过程无影响,肾脏是法罗培南的主要排泄器官,连续多次给药在体内无蓄积,     

Kinetics of canrenone after single and multiple doses of spironolactone

Summary In Study I 20 normal volunteers received a single oral dose of spironolactone 100 mg. In Study II a further 20 normal volunteers were given first spironolactone 100 mg b.i.d. and subsequently spironolactone 100 mg once a day for a further 4 days. In Study III 5 normal subjects were given a single dose of spironolactone 500 mg. The concentration of canrenone in serum was determined both by fluorimetry and HPLC for 0–48 h in Study I, 120–168 h in Study II and 0–36 h in Study III. The total AUCs after the single 100 mg dose did not differ from the AUCs within the dosing interval during steady state. The half-lives of the terminal log-linear phases were almost identical (14.99±0.80 h and 15.69±0,80 h) when determined by fluorimetry, and were sligthly, but significantly (p<0.01), longer when determined by HPLC — 20.14±1.62 and 18.71±1.04. The mean ratio of the specific AUC determined by HPLC and the fluorimetrically determined AUC was 0.3 after the single 100 mg dose. It did not differ from the corresponding value during steady state (0.34). In contrast, the ratio after the single 500 mg dose was approximately 50% higher. Fluorimetrically determined AUCs after 100 and 500 mg doses did not show dose-proportionality in contrast to the HPLC-determined AUCs. It was concluded that Canrenone contributes much less to the conventional fluorimetric determination than was previously assumed. It may not provide more than 1/10 and 1/4 of the antimineralocorticoid activity of spironolactone after single dose and multiple doses, respectively. Whereas linear kinetics apply after single and multiple 100 mg doses of spironolactone, after 500 mg saturation kinetics must be assumed with respect to metabolism. Thus, in bioavailability studies high doses of spironolactone should be avoided. For such studies the fluorimetric assay seems to be the appropriate bioanalytical method in spite of its lower specificity.First presented at the 20th Spring Meeting of the German Pharmacology Society, Mainz, March 20–23, 1979.     

Pharmacokinetics of fluoride in man after single and multiple oral doses

Summary The doses of fluoride (F) recommended in the literature for caries prevention and for the treatment of osteoporosis vary. This partly reflects inadequate knowledge of F pharmacokinetics. In the present study various single and multiple oral doses of F were given to eight volunteers, who had a strictly controlled F intake in the diet. The resulting plasma and parotid saliva concentrations as well as urinary output of F were measured. The plasma data fitted a two-compartment open model with a -slope half-life ranging between 2 and 9 h. Plasma clearance was 0.15±0.02 (SD) liter/kg/h. Data from the highest dose (10 mg) were fitted to both two- and three-compartment models, and there was no significant difference between them. Multiple doses of F 3.0 or 4.5 mg yielded steady state concentrations ranging from 54 to 145 ng/ml. About 50 per cent of the given dose was recovered in the urine, which is indicative of considerable accumulation in the body. The saliva F/plasma F concentration ratio was 0.64 with a coefficient of variation of 5%.     

铝镁匹林片单剂量和多剂量人体药动学研究

目的:研究单剂量和多剂量铝镁匹林片(每片含阿司匹林81 mg,甘羟铝11 mg,重质碳酸镁22 mg)的人体药动学特征。方法:27名健康受试者随机等分成81,162和324 mg·d~(-1)三组,每日口服规定剂量的铝镁匹林片,连续7 d。采用HPLC-MS-MS法测定血浆阿司匹林和水杨酸浓度。结果:阿司匹林的T_(max)约30 min,t_(1/2)为17．4～29．8 min;水杨酸的t_(1/2)为3～4 h,T_(max)为30～60 min;各剂量组的C_(max)AUC,T_(max),t_(1/2)和Cl/F在给药后d1和d7均无显著性差异,t_(1/2)和Cl/F在三组间无显著性差异。结论:在本研究剂量范围内,阿司匹林和水杨酸呈线性动力学,连续服药未见体内蓄积。