Computer assisted quantitative densitometric analysis of 125I-apamin binding sites in the central nervous system.

The binding sites for 125I-monoiododerivative of apamin in the central nervous system of rat, guinea-pig, chicken and frog were analysed and compared by computer assisted quantitative densitometric autoradiography on X-ray film. The highest level of binding sites in the rat and guinea-pig brain was found in the limbic-olfactory system and in the substantia gelatinosa of the spinal cord. In the chicken brain apamin binds preferentially to the tectum opticum and nuclei isthmi.

ECoG spectral analysis of apamin effects on the rat brain with pretrigeminal or high spinal transection of the central nervous system.

Rats were injected into one lateral ventricle (icv) with apamin (50 and 100 ng per animal). The resulting desynchronization pattern in the electro-corticogram (ECoG) and the symptoms of apaminism (uncoordinated hypermotility and jerks) were monitored. The results of presented experiments contributed additional data concerning the topography of apamin effects.

[Interactions between herbicides and various of the most frequently used drug groups. I. Interactions between chronically administered herbicides: carbendazyme, 2,4-dichlorophenoxyacetic acid and 2,4,5-trichlorophenoxyacetic acid and drugs affecting the circulatory system].

The influence of chronically administered (6 weeks) herbicides (KAR, 2,4-D and 2,4,5-T) on pharmacological effects of quinidine, reserpine and strophantin K in mice and rats was examined in vivo. The investigated herbicides produced in mice an increase in acute toxicity of strophantin K, the acute toxicity of either reserpine oro quinidine being unchanged. The herbicides alone, after 6 weeks administration, significantly increased mean arterial pressure of rats, however the hypotensive response to reserpine was not statistically influenced in these animals as compared with controls.

Cardiovascular responses to morphiceptin in spontaneously hypertensive and normotensive rats.

In the urethane anesthetized spontaneously hypertensive rats (SHR) intraventricular injections of morphiceptin produced dose-related increase in heart rate and blood pressure. In contrary, intraventricular administration of morphiceptin in Wistar rats induced a fall in blood pressure and heart rate. Yohimbine antagonized pressor responses to morphiceptin in SHR.

The effects of D-phenylalanine and its derivatives on enkephalin degradation in vitro: relation to analgesia and attenuation of the morphine withdrawal syndrome.

The effect of D-Phenylalanine (D-Phe), putative carboxypeptidase A inhibitor and its four derivatives (T1-T4) on analgesia, development of tolerance and physical dependence to morphine, and on degradation of both exogenous and endogenous enkephalins was investigated. Systemic administration of either D-Phe or its derivatives produced naloxone-reversible analgesia in the hot-plate test in mice. Naloxone-precipitated morphine withdrawal syndrome was attenuated in mice after systemic subacute administration (7 days, 1.

Substance P, hexapeptide pGlu6(SP6-11), analgesia and serotonin depletion.

Substance P caused marked analgesic activity in rats after intraventricular administration and in mice after intraperitoneal injection. The hexapeptide pGlu6(SP6-11) was active in mice, but not in rats. Depletion of serotonin with p-chlorophenylalanine abolished the antinociceptive activity in mice, but not in rats, whereas lesion of raphe nuclei blocked the activity of substance P in the latter animals.

The influence of raphe nucleus lesions on fertility in the female rat.

By lesioning brain raphe nuclei, the effect of decreasing the activity of the serotoninergic (5-HT) system on the fertility of the female rat was investigated. The females were mated on the 10th day after lesioning. On both the 15th and 21st day of pregnancy the numbers of live and resorbed foetuses and the weights of placentas in the lesioned groups did not differ statistically as compared with the control group.

Lesion of locus coeruleus: the effect on pethidine and pentazocine analgesia.

Analgesic activity of pethidine and pentazocine in the locus coeruleus lesioned rats was evaluated. Bilateral destruction of locus coeruleus resulted in a marked decrease in noradrenaline content in forebrain but did not change significantly the levels of dopamine. Lesioned animals showed a marked decrease of predrug pain threshold.

The effect of raphe nuclei lesions on the rat ovarian cycle.

The effects of lesions of the median raphe or dorsal raphe nuclei on ovarian cycle were studied in rats. Lesions involving raphe nuclei decreased forebrain 5-HT and 5-hydroxyindole acid (5-HIAA) concentrations. Rats with lesions of the raphe showed prolonged estrous phase as well as an increase in both the eosinophilic index and karyopycnotic index of the vaginal smears.

Preliminary screening of anticholinergic effect of new 1,3-dioxolane and 1,3,-dioxane derivatives.

Some of the 28 investigated new derivatives show distinct anticholinergic activity. The greatest activity, that of 2-cyclohexyl-2-phenyl-5-piperidinodioxane-1,3 was greater than of the atropine sulfate.

Antagonism by morphine and pethidine of the contractile effects of PGE2 on isolated uterus of the rat.

Morphine antagonizes the twitches evoked by administration of PGE2 on spontaneous contractile activity in the isolated uterus of the rat. This action is dose-dependent. Concentrations as low as 2.

The effects of lesion of mesolimbic dopamine neurons on pain threshold and morphine analgesia in rats.

Lesions of ventral tegmental area, localised in the region of A 10 group of dopaminergic mesolimbic neurons decreased the pain threshold in rats. The absolute threshold values in morphine treated animals with the above lesion were lower than in sham-operated controls, however, the thresholds expressed as percentage of predrug threshold values did not differ in both lesioned and sham-operated animals. It is thought, that lesions of ventral tegmental dopamine neurons decrease the pain threshold due to the increase of general excitability of animals, and that there is no direct involvement of the lesioned structure in the primary mechanism of morphine analgesia.

Central anticholinergic effects of N-ethyl-2-pyrrolidylmethyl-cyclopentylphenyl glycollate.

The following effects of N-ethyl-2-pyrrolidyl-methyl-cyclopentylphenyl glycollate (PMCG) have been studied: effects on aggressive behaviour in mice and on general behaviour in rats, protective effects against central action of arecoline and nicotine in mice, thermo-regulatory effects in mice, protective action in poisonings with fluostigmine in mice and rats, and effects on bioelectrical activity of the brain in cats. It was stated that PMCG possesses a strong central anticholinergic activity blocking predominantly central muscarinic receptors; PMCG had also strong protective effects in anticholinesterase intoxications. It is suggested that this drug could have antiemotional and antiparkinsonian properties.

Effects of lesions of monoaminergic system in the brain on the hypotensive effects of clonidine in rats.

Bilateral lesions of the locus coeruleus markedly reduced hypotensive effects of clonidine in rats. Lesions shifted laterally did not evoke any significant change of the hypotensive effects of clonidine or bradycardia induced by it. Lesions of the ventral and dorsal noradrenergic tract at the midbrain level and lesions of the midbrain raphe area failed to change hypotensive response to clonidine.