Effects of 18-hydroxydeoxycorticosterone on central nervous system excitability

Summary The effects of 18-hydroxydeoxycorticosterone (18-OH-DOC) on central nervous system excitability were studied in adrenalectomized rats. Sixty-four evoked potentials (EP) recorded from the pontine reticular formation were averaged before and after the injection of vehicle and hormone. 750 g of 18-OH-DOC dissolved in 0.5 ml of a 41 saline Cremophor-EL solution were injected i.v. A decrease of 55.7±6.1% in the amplitude of the EPs was observed with the hormone 16.3 min±2.7 (SE) after injection. Amplitude values returned to baseline levels 38 min±6.8 (SE) after injection. The secretion of 18-OH-DOC is greatly increased by ACTH and might modulate central nervous system function.     

Time and theophylline influence on the quantitative variations of the glomerular basement membrane ferritin pathway (author's transl)

A fine quantitative evaluation of ferritin aggregates in rat GBM permits to counts 5.08 +/- 1.51 and 18.30 +/- 3.21 g/cm2, respectively 30 and 60 min after ferritin injection; likewise, 30 min after ferritin administration, 5.08 +/- 1.51 and 17.11 +/- 3.9 g/cm2, respectively in normal and theophylline-treated animals.     

Dexamethasone suppression of ovulation in PMS-treated immature rats.

A single injection of 2.0 mg/kg dexamethasone (DXM) administered at 51 h after pregnant mare serum gonadatropin (PMS) treatment inhibited both ovulation and luteinization. S.c. injection of human chorionic gonadotropin (HGG) caused ovulation and luteinization in DXM-PMS-treated rats, whereas treatment with ACTH failed to overcome the DXM inhibitory effect. These findings are interpreted to indicate that DXM inhibits ovulation through a mechanism which might involve the central nervous system.     

Dexamethasone suppression of ovulation in PMS-treated immature rats

Summary A single injection of 2.0 mg/kg dexamethasone (DXM) administered at 51 h after pregnant mare serum gonadatropin (PMS) treatment inhibited both ovulation and luteinization. S.c. injection of human chorionic gonadotropin (HGG) caused ovulation ond luteinization in DXM-PMS-treated rats, whereas treatment with ACTH failed to overcome the DXM inhibitory effect. These findings are interpreted to indicate that DXM inhibits ovulation through a mechanism which might involve the central nervous system.     

The distribution of carcinogens, 4-nitroquinoline-1-oxide and 4-hydroxyaminoquinoline-1-oxide, in the nervous system and its possible neurotoxicological significance.

4-NQO-14C can enter the grey matter parenchyma of the central nervous system of mice after i.v. injection. The level of its uptake by the central grey is higher than that taken up by the central white and by the trigeminal and spinal dorsal root ganglia. This pattern of distribution is strikingly different from that obtained after i.v. injection of 4-HAQO-14C, suggesting the possible occurrence of 4-NQO encephalomyelopathy having entirely different sites of lesions from those of 4-HAQO neuropathy.     

Human growth hormone in urine: development of an ultrasensitive radiometric assay

An immunoradiometric assay for human growth hormone (HGH) has been developed which has a detection limit of 1 ng/l and can measure HGH in unextracted urine from normal children and adults. The assay is based on a two-step procedure, using a solid-phase goat-anti-HGH immunosorbent for immunoextraction and [125I]-labeled monoclonal HGH-antibody for detection and quantification. The assay is not affected by urea, NaCl or changes of pH from 5-8. The mean urine HGH concentration in normal children is 6.78 +/- 7.6 (SD) pg/ml, in patients with HGH-deficiency 1.3 +/- 0.9 pg/ml which increases to 11.7 +/- 13.4 pg/ml on the day of growth hormone injection.     

The distribution of carcinogens, 4-nitroquinoline-1-oxide and 4-hydroxyaminoquinoline-1-oxide,in the nervous system and its possible neurotoxicological significance

Summary 4-NQO-¹⁴C can enter the grey matter parenchyma of the central nervous system of mice after i.v. injection. The level of its uptake by the central grey is higher than that taken up by the central white and by the trigeminal and spinal dorsal root ganglia. This pattern of distribution is strikingly different from that obtained after i.v. injection of 4-HAQO-¹⁴C, suggesting the possible occurrence of 4-NQO encephalomyelopathy having entirely different sites of lesions from those of 4-HAQO neuropathy.This work was supported by a grant-in-Aid for Special Project Research from the Ministry of Education, Science and Culture of the Japanese Government (No. 321304, 1978).     

Adaptation of the deoxyglucose method to the cellular level: histologic preparation of the central nervous system for high resolution radioautography]

Vascular perfusion of all products required for primary fixation, postfixation, dehydration and embedding of nervous tissue in Epon permits radio-autographic detection of radioactivity accumulated in the central nervous system after intravenous injection of [3H]deoxyglucose. This histological technique should allow application of the deoxyglucose method at cellular if not subcellular level, since a high proportion of the tracer appears to be retained in situ in specimens adequately preserved for light and electron microscope radio-autography.     

Latent iron deficiency alters gamma-aminobutyric acid and glutamate metabolism in rat brain

A diet containing 18-20 mg iron/kg to young weaned rats for 8 weeks altered the metabolism of gamma-aminobutyric acid and glutamate in the central nervous system without affecting blood hemoglobin. Subsequent rehabilitation with 390 mg iron/kg diet for 2 weeks normalized these changes.     

Application to the study of connections in the CNS of the retrograde axonal transport of an iron-dextran complex]

The retrograde axonal transport of an iron-dextran complex was observed in neurons of the substantia nigra and of the intralaminar nuclei of the thalamus, after previous injection into the striatum. The histochemical demonstration of iron is simple and rapid, and can be combined with that of horseradish peroxidase, under precise conditions in the sequence of reactions. The iron-dextran complex revealed to be a valuable material for neuronal connectivity studies in the central nervous system.     

Nuclear localization of aldosterone in rat brain cells assessed by autoradiography.

Autoradiographic studies with 3H aldosterone demonstrate nuclear concentration of hormone in neurons of the hippocampus, septum, allocortical regions and brain stem reticular formation and motor nuclei of cranial nerves and in the meninges. The results suggest that mineralocorticoids have wide ranging effects on different parts of the central nervous system.     

The corticotropin-releasing factor (CRF) family of peptides as local modulators of adrenal function

Corticotropin-releasing factor (CRF), also termed corticotropin-releasing hormone (CRH) or corticoliberin, is the major regulator of the adaptive response to internal or external stresses. An essential component of the adaptation mechanism is the adrenal gland. CRF regulates adrenal function indirectly through the central nervous system (CNS) via the hypothalamic-pituitary-adrenal (HPA) axis and via the autonomic nervous system by way of locus coeruleus (LC) in the brain stem. Accumulating evidence suggests that CRF and its related peptides also affect the adrenals directly, i.e. not through the CNS but from within the adrenal gland where they form paracrine regulatory loops. Indeed, CRF and its related peptides, the urocortins (UCNs: UCN1, UCN2 and UCN3), their receptors CRF type 1 (CRF₁) and 2 (CRF₂) as well as the endogenous pseudo-receptor CRF-binding protein (CRF-BP) are all expressed in adrenal cortical, medullary chromaffin and resident immune cells. The intra-adrenal CRF-based regulatory system is complex and depends on the balance between the local concentration of CRF ligands and the availability of their receptors. Received 19 December 2006; received after revision 20 February 2007; accepted 26 March 2007     

Differences in luteinizing hormone release stimulated in rat anterior pituitary cells by leukotriene C4 and by gonadotropin-releasing hormone in vitro

Continuous administration of leukotriene C4 (LTC4, 10(-10) M) to superfused rat anterior pituitary cells increased LH release for 40 min only, whereas in a parallel experiment gonadotropin-releasing hormone (GnRH, 10(-9) M) evoked a continuous increase in hormone secretion. In contrast to GnRH, LTC4 did not desensitize rat anterior pituitary cells. The secretory action resulting from the administration of LTC4 (10(-10) M) was abolished for 40 min after previous stimulation. The results documented the dual action of LTC4 on LH exocytosis.     

Beta-endorphin in normozoospermic and pathologic human semen

beta-Endorphin was estimated in normozoospermic, oligozoospermic and azoospermic human semen. The mean amount in normozoospermic specimens was 278.6 +/- 43.6 (SE) pg/ml while in the others only 191.1 +/- 25 pg/ml. Both values are significantly higher than those present in the blood.     

Tetanus intoxication causes an increment of serotonin in the central nervous system

Summary Mice injected with tetanus toxin (TTx) showed an increase of 5-hydroxytryptamine (serotonin, 5-HT) levels in the central nervous system. The increment was not uniform thoughout the central nervous system. Particularly significant were the 25% and 80% increases observed, respectively, in whole brain and spinal cord. The levels of dopamine and norepinephrine remained unchanged. The subsequent studies of 5-HT turnover revealed a synthesis rate in the tetanic animals that was almost double that of controls. The degradation rate of the amine as well as the levels of 5-hydroxyindolacetic acid were unaffected.     

Tetanus intoxication causes an increment of serotonin in the central nervous system

Mice injected with tetanus toxin (TTx) showed an increase of 5-hydroxytryptamine (serotonin, 5-HT) levels in the central nervous system. The increment was not uniform throughout the central nervous system. Particularly significant were the 25% and 80% increases observed, respectively, in whole brain and spinal cord. The levels of dopamine and norepinephrine remained unchanged. The subsequent studies of 5-HT turnover revealed a synthesis rate in the tetanic animals that was almost double that of controls. The degradation rate of the amine as well as the levels of 5-hydroxyindolacetic acid were unaffected.     

Effect of repeated electroconvulsive shock on plasma noradrenaline and adrenaline in man

Summary The concentration of noradrenaline (NA) and of adrenaline (A) in plasma was measured before and 3, 30 and 60 min after single and repeated electroconvulsive shocks (ECS). Single ECS resulted in an activation of the sympathoadrenal medullary system; however, after the treatment had been repeated 4 times there was evidence of a diminished response of the peripheral sympathetic nervous system in comparison to the response to the first ECS.     

Oxidative stress and impaired oligodendrocyte precursor cell differentiation in neurological disorders

Cellular and Molecular Life Sciences - Oligodendrocyte precursor cells (OPCs) account for 5% of the resident parenchymal central nervous system glial cells. OPCs are not only a back-up for the loss...     

Role of serotonin in the hepato-gastroIntestinal tract: an old molecule for new perspectives

Beside its role as a neurotransmitter in the central nervous system, serotonin appears to be a central physiologic mediator of many gastrointestinal (GI) functions and a mediator of the brain-gut connection. By acting directly and via modulation of the enteric nervous system, serotonin has numerous effects on the GI tract. The main gut disturbances in which serotonin is involved are acute chemotherapy-induced nausea and vomiting, carcinoid syndrome and irritable bowel syndrome. Serotonin also has mitogenic properties. Platelet-derived serotonin is involved in liver regeneration after partial hepatectomy. In diseased liver, serotonin may play a crucial role in the progression of hepatic fibrosis and the pathogenesis of steatohepatitis. Better understanding of the role of the serotonin receptor subtypes and serotonin mechanisms of action in the liver and gut may open new therapeutic strategies in hepato-gastrointestinal diseases. Received 15 August 2007; received after revision 1 November 2007; accepted 5 November 2007     

Nuclear localization of aldosterone in rat brain cells assessed by autoradiography

Summary Autoradiographic studies with³H aldosterone demonstrate nuclear concentration of hormone in neurons of the hippocampus, septum, allocortical regionss and brain stem reticular formation and motor nuclei of cranial nerves and in the meninges. The results suggest that mineralocorticoids have wide ranging effects on different parts of the central nervous system.This work was supported by the Medical Research Council of Canada and by PHS grant NS09914. We thank Ms Brenda McClain for technical assistance.