PubMed Health⌕ Search

Biomedical subjects

R Nissen

Publications and source records attributed to R Nissen.

At least 19 recordsLinked to original sources
PubMed1992

Rat supraoptic neurons are resistant to glutamate neurotoxicity.

Magnocellular neurosecretory cells of the supraoptic nucleus (SON) are thought to be endogenously resistant to glutamate toxicity. In this study, we sought physiological and morphological evidence of this resistance in rats that received multiple peri-nuclear injections of ibotenate. In this preparation, ibotenate produced a large necrotic zone encompassing the SON but not within the nucleus itself. Extracellular recordings in vivo from 68 'spared' SON neurons from lesioned rats revealed normal patterns of electrical activity. Intracellular analysis in vitro from 13 'spared' SON neurons indicated that their intrinsic membrane properties, osmosensitivity and spontaneous synaptic activity did not differ significantly from that of controls. We conclude that SON neurons retain both a morphological and a physiological resistance to glutamate neurotoxicity.

Animals↗
PubMed1992

Catecholamine depletion of the diagonal band reduces baroreflex inhibition of supraoptic neurons.

In the rat, neurons in the diagonal band of Broca (DBB) participate in baroreceptor-induced depression of spontaneous activity of vasopressin neurons in the supraoptic nucleus (SON). The present study examined the role of the catecholaminergic innervation of the DBB in this response. Male rats were anesthetized with pentobarbital (50 mg/kg ip) and stereotaxically injected in the DBB with either vehicle (2 microliters), 6-hydroxydopamine (6-OHDA; 4 micrograms/2 microliters), or 6-OHDA preceded 20 min earlier by desimipramine (25 mg/kg ip), a norepinephrine uptake inhibitor. Two weeks later, the rats were reanesthetized and a transpharyngeal approach was used for extracellular recording from SON neurons. In vehicle-injected controls, baroreceptor stimulation produced by brief increases in blood pressure from metaraminol injections (10 micrograms/10 microliters iv) transiently arrested the spontaneous activity of 24 of 24 phasically active neurons tested. Sixty-three percent of the vasopressin neurons were not affected by comparable increases in blood pressure in 6-OHDA-treated rats, and the norepinephrine content of the DBB was significantly reduced. In experiments with desimipramine-pretreated rats, 92% of the vasopressin neurons were silenced by increases in blood pressure while the norepinephrine content of the DBB was not affected. Thus the noradrenergic innervation of DBB appears to participate in the baroreceptor sensitivity of SON vasopressinergic neurons.

Animals↗
PubMed1989

[Post-traumatic edema as a limiting factor in early functional treatment measures and its pharmacodynamic modification].

Post-traumatic oedema is a limiting factor of early functional exercise following fractures. A review of drug prophylaxis used in many clinical studies is given. A 30% reduction of oedema development following bimalleolar fractures was achieved with cyclooxigenase inhibitors (azapropazone) and aprotinin. It is pointed out that non-steroidal antiphlogistic drugs inhibit the collagen metabolism during the healing of rat skin-wounds.

Ankle Injuries↗
PubMed1978

Increased turnover of arterial collagen in hypertensive rats.

The turnover of total collagen in several tissues of 12-week-old normotensive and hypertensive rats was estimated by using tritium-labeled proline as a precursor. The effect of reutilization of the label was minimized by treatment with large doses of unlabeled proline subsequent to administering the radioactive imino acid. The collagen from skin, tail tendon, aorta, and mesenteric artery in normotensive animals had a half-life of about 60--70 days. In hypertensive animals the half-lives of skin and tail tendon collagen were unchanged but the half-lives of collagen in the aorta and mesenteric artery were reduced to 17 days.

Animals↗
PubMed1977

[Peptidyl prolyl hydroxylase activity in relation to the actual collagen biosynthesis in cotton pellet granuloma of guinea pig (author's transl)].

During the different stages of granuloma formation peptidyl prolyl hydroxylase activity and neutral salt soluble collagen were determined in the granuloma tissue. In parallel peptidyl prolyl hydroxylase activity, "collagen-like protein", and free hydroxyproline were measured in the serum of the same animals at correspondant time distances. A close correlation was found between the enzyme activity and the other parameters of collagen synthesis. These results confirm the conclusion that hydroxylation of polypeptide may be a rate limiting step in collagen biosynthesis. In addition the investigations revealed a close correlation between enzyme activity in the tissue and enzyme activity in the serum.

Animals↗
PubMed1977

[20 years in the management of reflux disease using fundoplication].

During the past twenty years fundoplication has found widespread propagation. Due to its effectiveness it is today the most often applied operative procedure of reflux-preventing surgery. As such the method must be reserved for clearly demonstrated reflux disease and its organic complications. False indication and incorrect technique have burdened results of such operations with unnecessary complications. The steps to a successful surgical reconstruction of the cardia are thus shown. In the future, the results of this surgical method will have to be improved more by correct indication instead of changing the surgical technique.

Esophagitis, Peptic↗