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Biomedical subjects

M Morris

Publications and source records attributed to M Morris.

At least 451 records · Page 25Linked to original sources
PubMed1977

Role of transmitters in mediating hypothalamic control of electrolyte excretion.

Changes in urinary volume and electrolyte excretion were monitored after the injection of cholinergic and monoaminergic drugs into the third cerebral ventricle of conscious male rats made diuretic by an intravenous infusion of 5% dextrose. A natriuretic and kaliuretic response was induced by the intraventricular injection of norephrine (NE) or carbachol, whereas dopamine (DA) had no effect. The beta-receptor stimulator isoproterenol (ISO) induced an antinatriuretic and antikaliuretic effect. Intraventricular injection of the alpha-adrenergic blocker phentolamine abolished the natriuretic response to NE and carbachol and to intraventricular hypertonic saline (HS). By contrast, the beta-adrenergic blocker propranolol induced a natriuresis and kaliuresis when injected alone and an additive effect when its injection was followed by NE or HS. Propranolol potentiated the natriuretic response to carbachol. Cholinergic blockade with atropine diminished the response to NE and blocked the natriuretic response to HS. It is suggested that sodium receptors in the ventricular wall can modify renal sodium excretion via a stimulatory pathway involving cholinergic and alpha-adrenergic receptors and can inhibit sodium excretion via a tonically active beta-receptor pathway.

Animals↗
PubMed1976

The effects of pentobarbital and ether anesthesia on hypothalamic LH-RH in the rat.

The effects of ether and pentobarbital anesthesia on hypothalamic and cerebrospinal fluid (CSF) LH-RH content were studied in male rats. Ether elevated hypothalamic LH-RH 30 min after a 3-min exposure; pentobarbital (30 mg/kgital (30mg/kg) caused no change. The ether-induced increase in LH-RH content was not affected by pretreatment with pentobarbital; however, the increase was abolished in animals subjected to hypothalamic deafferentation. Changes in CSF LH-RH generally paralleled the hypothalamic changes; ether, for example, elicited a significant rise. These results demonstrate the complex hypothalamo-pituitary-CSF interactions which occur in response to general anesthetics.

Animals↗
PubMed1976

Renin and hemodynamic changes via central adrenergic, cholinergic, and sodium receptor mechanisms in conscious rats.

The effects of centrally administered autonomic drugs and hypertonic saline on renin release were studied in the conscious rat. A 0.3 mug intraventricular dose of isoproterenol, which is one-thirtieth of the intraperitoneal dose required to stimulate renin release, induced the release of renin into the systemic circulation. Norepinephrine had no effect on renin release in the same dose range. Hypertonic saline and carbachol suppressed renin release. Alterations in renin release were preceded by a reciprocal change in blood pressure. These results suggest a central nervous system site for sodium, beta-adrenergic, and cholinergic receptors in altering renin release and blood pressure.

Adrenergic Agonists↗
PubMed1976

Evidence for hormonal participation in the natriuretic and kaliuretic responses to intraventricular hypertonic saline and norepinephrine.

To examine if hypothalamic or pituitary hormones are involved in the induction of the natriuresis which follows the injection of hypertonic saline or norepinephrine into the third ventricle, lesions were placed in the median eminence and the responses to intraventricular norepinephrine or hypertonic saline were evaluated. Sham lesions in which the electrode was lowered into the brain but stopped short of the hypothalamic region did not interfere with the natriuresis, kaliuresis, and antidiuresis induced by the third ventricular injection of either hypertonic sodium chloride or norepinephrine. Lesions in the median eminence which induced diabetes insipidus as evidenced by an increase in water consumption to approximately four times normal completely abolished the natriuresis and kaliuresis in response to intraventricular hypertonic saline or norepinephrine and diminished the antidiuresis. The observations suggest the possibility that a natriuretic hormone(s) is involved in the induction of central natriuresis.

Animals↗
PubMed1975

Mum's army.

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History of Nursing↗
PubMed1975

Modification of brain and CSF LH-RH following deafferentation.

The effect of hypothalamic deafferentation upon levels of LH-RH in brain, cerebrospinal fluid, and plasma was studied in adult male rats. Deafferentation produced a significant increase in the LH-RH concentration of third ventricular CSF (from 140.6 to 343.9 pg/microl), while there was no change in median eminence or hypothalamic content. LH-RH in the pineal gland and the posterior pituitary was also elevated by hypothalamic isolation.

Animals↗