EFFECTS OF PROGESTERONE AND PENTOBARBITONE ON HYPOTHALAMIC INDUCTION OF OVULATION IN THE 5-DAY CYCLIC RAT

1967 ◽  
Vol 55 (3) ◽  
pp. 378-388 ◽  
Author(s):  
G. H. Zeilmaker ◽  
J. Moll
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Median Eminence ◽  
Preoptic Area ◽  
Experimental Conditions ◽  
Induced Ovulation ◽  
Ether Anaesthesia ◽  
Main Technique ◽  
The Central Nervous System ◽  
Stimulation Of

ABSTRACT The involvement of the central nervous system in the inhibitory effects on ovulation of progesterone and pentobarbitone was studied in 5-day cyclic rats. The occurrence of ovulation following electrochemical stimulation of the median eminence or the preoptic area was the main technique used in this work. The following experiments are reported. Following pretreatment with 10 mg progesterone on day 3 of the cycle stimulation of the preoptic area on day 4 was almost completely ineffective. However, stimulation of the median eminence was effective in most of these progesterone-treated rats (I). Following pretreatment with the much lower dose of 0.5 mg progesterone, spontaneous ovulation was still suppressed. However, stimulation of the preoptic area was now capable of inducing ovulations in most animals, but only if ether anaesthesia was used during the stimulation procedure. If combined pentobarbitone-ether anaesthesia was used, most animals did not ovulate (II). In other experiments stimulation of the median eminence or preoptic area was performed on day 3 (dioestrus) under ether anaesthesia or combined pentobarbitone-ether anaesthesia in normally cycling rats, which did not receive progesterone. Under ether anaesthesia preoptic stimulation induced ovulation in most animals, but under combined pentobarbitone-ether anaesthesia none of the animals ovulated (III). Stimulation in the median eminence under otherwise identical experimental conditions, induced ovulation without exceptions under ether anaesthesia and in half of the cases operated under combined pentobarbitone-ether anaesthesia (IV). It is concluded that these findings support the concept that the inhibitory effect of progesterone on ovulation is due to an action on the central nervous system. Furthermore, consideration of the possible mechanisms of action of progesterone and of pentobarbitone in inhibiting ovulation led to two alternative hypotheses: the two substances exert their effect on ovulation at the same site, or, pentobarbitone acts at a level closer to the median eminence.

scholarly journals VI. —Anaphylaxis and anaphylatoxins

1923 ◽  
Vol 211 (382-390) ◽  
pp. 273-315 ◽  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Guinea Pig ◽  
Anaphylactic Shock ◽  
The Body ◽  
Muscle Fibres ◽  
Direct Stimulation ◽  
Fundamental Conception ◽  
The Central Nervous System ◽  
Stimulation Of

In the study of the phenomena of anaphylaxis there are certain points on which some measure of agreement seems to have been attained. In the case of anaphylaxis to soluble proteins, with which alone we are directly concerned in this paper, the majority of investigators probably accept the view that the condition is due to the formation of an antibody of the precipitin type. Concerning the method, however, by which the presence of this antibody causes the specific sensitiveness, the means by which its interaction with the antibody produces the anaphylactic shock, there is a wide divergence of conception. Two main currents of speculation can be discerned. One view, historically rather the earlier, and first put forward by Besredka (1) attributes the anaphylactic condition to the location of the antibody in the body cells. There is not complete unanimity among adherents of this view as to the nature of the antibody concerned, or as to the class of cells containing it which are primarily affected in the anaphylactic shock. Besredka (2) himself has apparently not accepted the identification of the anaphylactic antibody with a precipitin, but regards it as belonging to a special class (sensibilisine). He also regards the cells of the central nervous system as those primarily involved in the anaphylactic shock in the guinea-pig. Others, including one of us (3), have found no adequate reason for rejecting the strong evidence in favour of the precipitin nature of the anaphylactic antibody, produced by Doerr and Russ (4), Weil (5), and others, and have accepted and confirmed the description of the rapid anaphylactic death in the guinea-pig as due to a direct stimulation of the plain-muscle fibres surrounding the bronchioles, causing valve-like obstruction of the lumen, and leading to asphyxia, with the characteristic fixed distension of the lungs, as first described by Auer and Lewis (6), and almost simultaneously by Biedl and Kraus (7). But the fundamental conception of anaphylaxis as due to cellular location of an antibody, and of the reaction as due to the union of antigen and antibody taking place in the protoplasm, is common to a number of workers who thus differ on details.

scholarly journals The life history of Hepatozoon leptodactyli (Lesage, 1908) Pessoa, 1970: a parasite of the common laboratory animal: the frog of the genus Leptodactylus

1973 ◽  
Vol 71 (1-2) ◽  
pp. 1-8 ◽  
Author(s):  
Sylvio Celso Goncalves da Costa ◽  
Samuel B. Pessoa ◽  
Neize de Moura Pereira ◽  
Tania Colombo
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Life History ◽  
Laboratory Animal ◽  
Peripheral Circulation ◽  
Experimental Conditions ◽  
History Of ◽  
The Central Nervous System ◽  
The Common ◽  
Common Laboratory

The main object of the present paper is to furnish a brief account to the knowledgement of Protozoa parasitic in common Brazilian frog of the genus Leptodactylus for general students in Zoology and for investigators that use this frog as a laboratory animal. Hepatozoon leptodactyli (Haemogregarina leptodactyli) was found in two species of frogs - Leptodactylus ocellatus and L. pentadactylus - in which develop schizogony whereas sporogony occurs in the leech Haementeria lutzi as was obtainded in experimental conditions. Intracellular forms have been found in peripheral circulation, chiefly in erythrocytes, but we have found them in leukocytes too. Tissue stages were found in frog, liver, lungs, spleen, gut, brain and heart. The occurence of hemogregarine in the Central Nervous System was recorded by Costa & al,(13) and Ball (2). Some cytochemical methods were employed in attempt to differentiate gametocytes from trophozoites in the peripheral blood and to characterize the cystic membrane as well. The speorogonic cycle was developed in only one specie of leech. A brief description of the parasite is given.

Blood Pressure and Pulse Rate in the Foetal Sheep

1945 ◽  
Vol 22 (1-2) ◽  
pp. 63-74
Author(s):  
JOSEPH BARCROFT ◽  
D. H. BARRON
Keyword(s):  
Blood Pressure ◽  
Central Nervous System ◽  
Nervous System ◽  
Pulse Rate ◽  
Umbilical Artery ◽  
The Central Nervous System ◽  
The Right ◽  
First Moment ◽  
Left Vagus ◽  
Stimulation Of

1. A method (the needle method) is described for the measurement of the pressure in the stream going through a vessel. 2. In the foetal sheep the needle method applied to the umbilical artery gives substantially the same results as the mercurial manometer applied to the carotid, until about half-way through the gestation period. 3. As gestation proceeds the needle method applied at the first moment at which it can be applied to the umbilical artery (or a branch) gives readings substantially lower, and increasingly lower as gestation proceeds, than does the mercurial manometer read at the first moment at which it can be read. 4. The discrepancy is due to the sum of a number of causes which are discussed, but of these the most important is an actual rise of pressure between the time of delivery and the completion of the dissections contingent on the use of the mercurial manometer. 5. The cause of this is not at present demonstrated, but either or both of two factors may be concerned: (a) a dulling of the central nervous system which weakens the depressor reflex; (b) the establishment of a greater degree of vasomotor tone consequent on the bombardment of the central nervous system with sensory stimuli. 6. The pulse rates in utero and just after delivery of the foetus into a saline bath at 39-40°C. (the umbilical circulation being unimpaired) are not significantly different. 7. The pulse rate quickens up to the 70th-80th day, after which it becomes slower as gestation proceeds. 8. If both vagi be severed, the pulse rate te to quicken throughout gestation. The pulse, therefore, comes increasingly under vagus inhibition from the 80th-90th day onwards. 9. Even after the vagi have been cut after the 120th day (it has not been tried before) adrenalin in sufficient quantity will cause a further quickening of the pulse. 10. The earliest date at which stimulation of the peripheral end of the right vagus was observed to slow the heart was the 77th day. On the 85th day peripheral stimulation of the left vagus also failed, but succeeded on the 101st day. 11. Central stimulation of the left vagus, with the right vagus intact, produced slowing on the 77th day. 12. Slowing of the heart synchronous with rise of arterial pressure has been observed on the 111th day. 13. Slowing of the heart which bears evidence of being reflex has been obtained by raising the blood pressure (clamping the cord) on the 121st day and by injection of adrenalin on the 118th day. 14. Approaching term both the carotid sinus and cardiac depressor mechanisms are functional. 15. Lowering of the blood pressure as the result of stimulation of the central end of the vagus and with both vagi severed can be demonstrated late in gestation.

Optical Stimulation of the Central Nervous System In Vitro

2008 ◽  
Author(s):  
Jonathan M. Cayce ◽  
Chris Kao ◽  
Jonathan D. Malphurus ◽  
Peter Konrad ◽  
Duco Jansen ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Optical Stimulation ◽  
The Central Nervous System ◽  
Stimulation Of

scholarly journals A STRUCTURAL ANALYSIS OF THE MYELIN SHEATH IN THE CENTRAL NERVOUS SYSTEM

1967 ◽  
Vol 34 (2) ◽  
pp. 555-567 ◽  
Author(s):  
Asao Hirano ◽  
Herbert M. Dembitzer
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Electron Microscope ◽  
Myelin Sheath ◽  
Cerebral White Matter ◽  
Experimental Conditions ◽  
Myelin Sheaths ◽  
Basic Theme ◽  
Cell Processes ◽  
The Central Nervous System

The cerebral white matter of rats subjected to a variety of noxious experimental conditions was examined in the electron microscope. Several unusual configurations of the myelin sheath are identified in addition to the usual configuration. These variations include the presence of (a) formed organelles within the inner and outer loops, (b) isolated islands of cytoplasm in unfused portions of the major dense lines, (c) apparently unconnected cell processes between the sheath and the axon, and (d) concentric, double myelin sheaths. A generalized model of the myelin sheath based on a hypothetical unrolling of the sheath is described. It consists of a shovel-shaped myelin sheet surrounded by a continuous thickened rim of cytoplasm. Most of the unusual myelin configurations are explained as simple variations on this basic theme. With the help of this model, an explanation of the formation of the myelin sheath is offered. This explanation involves the concept that myelin formation can occur at all cytoplasmic areas adjacent to the myelin proper and that adjacent myelin lamellae can move in relation to each other.

scholarly journals Therapeutic electrical stimulation of the central nervous system

2005 ◽  
Vol 328 (2) ◽  
pp. 177-186 ◽  
Author(s):  
Alim-Louis Benabid ◽  
Bradley Wallace ◽  
John Mitrofanis ◽  
Celine Xia ◽  
Brigitte Piallat ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Electrical Stimulation ◽  
The Central Nervous System ◽  
Stimulation Of
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