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Biomedical subjects

O Günther

Publications and source records attributed to O Günther.

At least 19 recordsLinked to original sources
PubMed1990

ADH, renal, and circulatory responses to adrenergic stimulation in anterior third ventricle.

The anterodorsal part of the third ventricle of conscious ducks was perfused intracerebroventricularly (icv) for 10 min with norepinephrine (NE) or with its agonists phenylephrine (alpha 1, Phe), isoproterenol (beta, Iso), and clonidine (alpha 2, Clo) in artificial CSF (aCSF). Their effects on the plasma level of antidiuretic hormone (AVT, arginine vasotocin in birds), urine excretion, heart rate (HR), and mean arterial pressure (MAP) were investigated in steady-state water diuresis. The correct position of the icv cannula was confirmed by enhanced AVT release and antidiuresis in response to icv perfusion of aCSF made hypertonic (400 mosmol/kgH2O) by adding NaCl. Icv perfusion with hypertonic aCSF and 750 ng/min NE had comparable effects on AVT release and urine excretion, but hypertonic aCSF caused small increases in MAP and HR, whereas NE depressed both MAP and HR. Antidiuresis and circulatory depression caused by NE icv perfusion was dose dependent. Among the adrenergic agonists perfused at similar doses (188 ng/min), only Iso stimulated AVT release. Iso and Phe had small depressive effects on MAP and HR (less than 10%). Clo depressed circulation by greater than 20% for longer than 60 min, and AVT release became significantly reduced 30 min after the start of icv perfusion. The consistent results in ducks contrast with the equivocal data hitherto reported for central stimulations with NE or its agonists in mammals and may be due to the concentric perfusion system used in our study for localized stimulations in the vicinity of the paraventricular nucleus.

Animals↗
PubMed1989

Osmotic and hormonal stimulation of the third ventricular region of ducks: antidiuretic, circulatory and local neuronal responses.

By means of local microperfusion of the 3rd cerebral ventricle, antidiuretic and circulatory responses to stimulations with various hypertonic solutions and norepinephrine were analyzed in conscious ducks. The results suggest ionic rather than osmometric responsiveness of periventricular osmoreceptive elements, which is in line with single unit recordings of periventricular neurons tested in vitro for their osmoresponsiveness. These neurons were located subependymally at the site of greatest responsiveness in vivo, and corresponded to morphologically identified neurons projecting to the neuroendocrine hypothalamo-pituitary system. Antidiuresis was combined with increases in arterial pressure and heart rate in response to hypertonic stimulations with monovalent cations; divalent cations produced long-lasting antidiuresis and equivocal circulatory responses. Norepinephrine elicited antidiuresis which was accompanied by arterial hypotension and bradycardia. Osmotically and norepinephrine induced antidiuresis was combined with increases of plasma ADH concentration. Different modulatory actions of intrinsic adrenergic, angiotensinergic and vasotocinergic neurons are suggested in hypothalamic control of autonomic functions.

Angiotensin II↗
PubMed1988

Differential effect of vasopressin on open-field activity and passive avoidance behaviour following intracerebroventricular versus intracisternal administration in rats.

The effects of lysine8-vasopressin (LVP) on the open-field activity and passive avoidance behaviour in rats were studied following intracerebroventricular (i.c.v.) and intracisternal (c.m.) administration. Following i.c.v. administration, LVP caused a long-lasting facilitation of the passive avoidance behaviour and did not influence open-field activity. When injected into the cisterna magna, on the other hand, the same amount of LVP was without effect on the passive avoidance behaviour, while decreasing open-field activity. It is concluded that the site of injection in the cerebrospinal space might be of importance in determining the behavioural effects of neuropeptides.

Animals↗
PubMed1987

[50 years of Garz theses].

50 years after the publication of the Garz theses by Gerhardt Katsch is tested what remains even nowadays still actual for the treatment of diabetics from the previous concept. It can be stated that the largest part of the then therapeutic recommendations since that time has frequently stood the test in practice and is in force still at present. This is of importance above all for the dietary regulations. - The Garz dietary prescriptions from 1930 to 1954 are summarizingly described here for the first time. They confirm the advantages of a fat restriction in the diabetes diet which are in general acknowledged at present.

Diabetes Mellitus↗
PubMed1986

The effect on brain 5-HT of central lysine-vasopressin administration into different cerebral ventricular compartments depends on the site of injection.

The influence of lysine-8-vasopressin (LVP) on the steady-state level of serotonin was studied in different brain regions four hours after microinjection into the lateral ventricle (icv) or cisterna magna (cm). LVP (200 pg) increased the serotonin (5-HT) level in the hypothalamus and mesencephalon after cm application, while icv administration caused an opposite tendency. The findings suggest that the site of peptide administration is of decisive importance in the mediation of various effects of LVP on the transmitter metabolism. A possible link exists between opposite effects of cm versus icv injection of LVP on central serotoninergic mechanisms, as well as on behavioral and autonomic correlates of these treatment.

Animals↗
PubMed1983

Vasopressin and oxytocin in cerebrospinal fluid and plasma of conscious rabbits--response to dehydration and haemorrhage.

Vasopressin and oxytocin were determined simultaneously by a radioimmunoassay in cerebrospinal fluid and plasma of conscious, unrestrained rabbits. An elevation of neuropeptide levels in plasma, but not in cerebrospinal fluid, in response to dehydration or haemorrhage suggests an independent regulation of vasopressin and oxytocin concentration in both body fluids.

Animals↗
PubMed1980

[Legionellaceae].

Explore the source record for details and available documents.

Bacteria↗