Helmut Coper

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Tolerance to various effects of morphine in the rat can be quantified by means of a shift of semilogarithmic dose-response curves. Tolerance to analgesia (hot plate, acetic acid writhing), catalepsy, and the tilted plane develops in a closely similar manner. Also, the stimulating effects of about 1 mg/kg morphine-HCl tested in an open-field procedure are(More)
The development of a differential tolerance to morphine was investigated with respect to the mean effective dose, the threshold dose of tolerance, the degree of tolerance after a fixed dose, and the speed of tolerance loss. The mean effective doses, the threshold doses of tolerance, and the degree of tolerance differed considerably from effect to effect,(More)
The aim of the study was to assess the contribution of central dopaminergic and glutamatergic systems to the age-dependent loss of motor functions in rats. Rats of three age groups were compared: young (3-5-month-old), middle-aged (20-21-month-old) and old (29-31-month-old). The obtained results showed an age-dependent decline in the electromyographic (EMG)(More)
As an example for a drug combination used as a sedative (Vesparax) the actions of secobarbital (S), brallobarbital (B) and the antihistamine etodroxizine (E) were studied in mice after single and concomitant oral application. S and B caused a dose-dependent increase of exploratory locomotor performance enclosing a short period of locomotor depression. Such(More)
Ontogenesis is closely related to the ability to adapt to endogenous and exogenous stimuli. However, this precondition for viability does not remain stable; it changes in correlation to the phases of life. In this long-term study with rats, the extent to which moderate prenatal damage influences the adaptability in the juvenile, adult and senile phases was(More)
The influence of two antihistamines on the oral intake of various drugs with addictive potency was investigated in rats. Under the chosen conditions neither tripelennamine nor diphenhydramine have reinforcing properties. The reinforcing potency of addictive drugs is not augmented by the both substances. On the contrary, in some cases they led to a decrease(More)
1. Tolerance to morphine-induced analgesia (hot plate and acetic acid whrithing test), hypothermia and lethality can be quantified in mice by measuring the degree of parallel shifts of semilog. dose-response relationships induced by repeated opioid administration. 2. A similar procedure can be used for the quantification of naloxone-induced withdrawal as an(More)
The kinetics and tissue distribution of amphetamine and its metabolites p-hydroxyamphetamine (p-OH-A) and p-hydroxynorephedrine (p-OH-NE) were investigated in young adult (3–4 months) and old (20–25 months) male rats, after i.p. injection of 5 mg/kg tritium labelled d-amphetamine. The concentrations of these drugs were determined in plasma, cerebral cortex,(More)
Female Wistar rats were treated chronically with d-amphetamine sulphate in drinking water. The concentrations of amphetamine were 0.01%, 0.02%, 0.03%, 0.04% and 0.05% in the 1st, 2nd, 3rd, 4th, and 5th week of treatment. The consumed doses of amphetamine increased from 16 mg/kg on the first day up to 90 mg/kg on the 36th day of treatment. The effects of(More)