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Under a scanning microscope, leaves from tissue cultures (after 8 weeks in vitro culturing), from 1 year old regenerants and from the 100 years old donor tree were studied. More abnormalities were observed in the tissue culture compared to regenerant and donor. During tissue culture transfer rapid, leaf dehydration occurs due to defective regulation mechanisms making stomata of tissue culture stay open. Epidermis as well as stomata cells were observed already on the leaves in in vitro conditions, but they become physiologically functioning only after transfer into conditions of natural environment.
BD-1158 is a new 1,4 benzodiazepine derivative. The purpose of the present experiments was to test the influence of this substance on the behaviour of rabbits under stress conditions, induced by electrical stimulation of ventromedial nucleus of the hypothalamus (VMH). The experiments were performed for 4 subsequent days in a group of 10 rabbits. On the first day the electrode was implanted into VMH. On the second day the spontaneous behaviour in stress conditions was tested. On the third day 1 ml of 1 % starch solution was administered intraperitoneally. On the fourth day BD-1158 was administered intraperitoneally at a dose 10mg/kg diluted in starch solution up to 1 ml, 35 minutes before the beginning of the experiment. Six phases of behaviour were estimated. It was concluded that in extreme conditons BD-1158 has a strong anxiolytic and sedative effect. lts influence concerns a considerable extension of the comfort phase and decrease of the tension phase. BD-1158 does not influence the animals' activity and attention (the orientation-searching phase and grooming). It decreases eating and drinking.
We investigated the role of interleukin-1ß (IL-1ß) and prostaglandins (PG) in the 1-adrenergic agonist, phenylephrine-induced hypothalamic-pituitary-adrenal axis (HPA) responses under basal and social stress conditions. Male Wistar rats, either control or exposed to crowding stress for 7 days prior to treatment, were used in these experiments. All compounds were injected i.p. Cyclooxygenase COX-1 and COX-2 inhibitors, piroxicam and compound NS-398, IL-1ß and IL-1ß receptor antagonist (IL-1ßRA) were injected 15 min before phenylephrine. Plasma ACTH and serum corticosterone levels were measured 1 h after phenylephrine or IL-1ß injection. Phenylephrine, in respective higher dose administered systemically (0.4 mg/kg i.p.) was almost equally effective as given i.c.v. (30 µg) in stimulating ACTH and corticosterone secretion. Likewise, the extent of the involvement of PG generated by COX-1 and COX-2 in the phenylephrine-induced ACTH and corticosterone secretion was similar after systemic or i.c.v. treatment under both resting and stress conditions. Piroxicam, stronger than compound NS-398, reduced the i.p. phenylephrine-induced ACTH and corticosterone secretion. IL-1ß receptor antagonist (50 µg/kg i.p.) did not significantly affect the inhibitory action of piroxicam on the i.p. phenylephrine-induced ACTH and corticosterone secretion in control rats, but significantly enhanced the inhibition evoked by piroxicam in stressed rats. IL-1ß (2.5 µg/kg i.p.) significantly increased ACTH and corticosterone secretion under basal conditions. Crowding stress for 7 days markedly impaired the IL-1ß-induced ACTH and corticosterone secretion. The mechanism of the stimulatory action of i.p. IL-1ß, which does not cross the blood-brain barrier, may comprise both central and peripheral components of the HPA axis. These results suggest that under basal conditions IL-1ß is not markedly involved in the 1-adrenergic agonist-induced stimulation of the HPA axis activity. During social crowding stress IL-1ß and prostaglandins are significantly involved in this stimulation.
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