[Effect of chronic exposure to nitrogen dioxide on biogenic amine levels in the brain of guinea pigs]. / Wplyw przewleklej ekspozycji dwutlenku azotu na zawartosc amin biogennych w mózgu swinek morskich.

The experiment was carried out on male guinea pigs exposed to NO2 at a constant concentration of 0.1 ppm 24 h daily for 1, 2.5 and 6 months, or NO2 concentration was increased to 0.5 ppm twice daily, between 7:00 and 8:00 AM and 4:00 and 5:00 PM. After the exposure to NO2 was over the animals were killed by decapitation. The cranium was opened and the brain removed, and afterwards at 0 degrees C the left hemisphere was dissected into discrete areas which were then frozen on dry ice and weighed. The tissues were kept for 2-3 days at -20 degrees C, and afterwards the content of noradrenaline, 5-hydroxytryptamine and 5-hydroxyindole-acetic acid was estimated spectrofluorometrically in examined parts of the brain (thalamus--hypothalamus pons + medulla oblongata hippocampus, cortex frontalis). It was shown that the applied NO2 concentrations brought about slight and nonspecific alterations in the content of the investigated amines in guinea pigs' brain.

Central action of melanostatin (MIF-1) in mice.

The effects of MIF-1 administered into a lateral ventricle of the brain were studied on the behaviour of mice in the open field test and hole test, apomorphine-induced stereotypy, morphine-induced catalepsy, and reactivity on thermal painful stimuli in the hot plate test. The last test was compared with a similar test with morphine administration. It was demonstrated that MIF-1 exerted a depressing effect on the behaviour of mice, increased the intensity of apomorphine-induced stereotypy and weakened chlorpromazine-induced catalepsy. Moreover, an analgesic action of MIF-1 was demonstrated which was blocked with naloxone. The results of these investigations indicated a significant central action of MIF-1 in mice and a participation of dopaminergic receptors in certain effects of MIF-1 on the behaviour of experimental animals.

The diuretic action of noradrenaline and dopamine in rats with chemical serotoninectomy and central nervous system sympathectomy.

It was demonstrated that dopamine administered into the lateral ventricle of rats with chemically induced sympathectomy of the central nervous system had an evident diuretic effect observed 4 as well as 24 hours after its injection. Noradrenaline, on the other hand, increased diuresis in control rats and in those with chemical serotoninectomy, but only in the first 4 hours of the experiment. Chemical sympathectomy of the central nervous system abolished the diuretic effect of noradrenaline. The results of the experiment confirm the role of mainly dopaminergic receptors in the central regulation of diuresis in this experimental model.

The effect of prostaglandins on climbing behavior induced by apomorphine in mice.

Prostaglandins E2, F2 alpha, D2 and I2 administered intracerebroventricularly in a dose of 1 microgram, inhibited the climbing behavior induced by apomorphine. The most active in this respect was PGE2, the least--PGD2. The results indicate the participation of prostaglandins in the regulation of central dopaminergic function.