Concluding remarks

1958 ◽  
Vol 149 (936) ◽  
pp. 424-424
Keyword(s):  
The Other ◽  
Wide Field ◽  
Present Position ◽  
Special Volume ◽  
Milk Ejection ◽  
Hormonal Factors ◽  
Metabolic Hormones ◽  
Milk Ejection Reflex ◽  
The One ◽  
Stimulation Of

Our discussion to-day has ranged over a wide field, extending from pure endocrinology on the one hand, to biochemistry on the other, and we have had excellent summaries of the present position regarding various aspects, endocrine, neuroendocrine and biochemical, of research on the mammary gland. It is interesting to recall that in 1950 a conference on the Mécanisme Physiologique de la Sécrétion Lactée was held at Strasbourg under the auspices of the Centre National de la Recherche Scientifique of France. This conference lasted a week and some of those taking part in to-day’s discussion also participated in the conference at Strasbourg. The proceedings of this conference were published in the form of a special volume. It is instructive to compare the state of knowledge of our subject in 1950 with what we know to-day and thus to gain an idea of the progress made during the intervening period. Dr Lyons had by then begun his elegant analysis of the hormonal factors responsible for mammary growth in the hypophysectomized rat, but his paper to-day shows how much more is now known about the hormonal interrelationships involved. Little was then known about the effects on mammary growth of metabolic hormones such as insulin and the adrenal corticoids. Moreover, work on the maintenance of lactation in hypophysectomized animals had hardly then begun. As regards the milk ejection reflex, the experiments of Cross & Harris on the electrical stimulation of the neurohypophysis which did so much to advance our knowledge of this aspect, was only then beginning and was briefly referred to during the discussion at Strasbourg.

scholarly journals A NEW FREEZING-ULTRAMICROTOME

1961 ◽  
Vol 10 (1) ◽  
pp. 1-13 ◽  
Author(s):  
H. Moor ◽  
K. Mühlethaler ◽  
H. Waldner ◽  
A. Frey-Wyssling
Keyword(s):  
The Other ◽  
Wide Field ◽  
Cell Organelles ◽  
Electron Microscopic ◽  
Preliminary Results ◽  
Biological Objects ◽  
Shadow Casting ◽  
Internal Structures ◽  
The One ◽  
Microscopic Investigations

The difficulties in sectioning frozen biological objects for electron microscopic investigations are overcome by Steere's freezing-etching method. In order to test this method and to open up a wide field of application, the new freezing-ultramicrotome has been designed. The apparatus consists of the combination of an ultramicrotome with freezing-drying and shadow-casting installations in the same vacuum container. The preliminary results show, on the one hand, the practicability of all preparational steps and, on the other, that it is possible to resolve internal structures of cell organelles and even macromolecular patterns.

scholarly journals The influence of homodromous and heterodromous electric currents on transmission of excitation in plant and animal

1915 ◽  
Vol 88 (607) ◽  
pp. 483-507 ◽  
Keyword(s):  
Electric Current ◽  
The Other ◽  
Muscle Preparation ◽  
Mimosa Pudica ◽  
Electric Currents ◽  
Joint Effects ◽  
Conducting Tissue ◽  
The One ◽  
Conduction Of Excitation ◽  
Stimulation Of

I have in a previous paper described investigation on the conduction of excitation in Mimosa pudica . It was there shown that the various characteristics of the propagation of excitation in the conducting tissue of the plant are in every way similar to those in the animal nerve. Hence it appeared probable that any newly found phenomenon in the one case was likely to lead to the discovery of a similar phenomenon in the other. A problem of great interest which has attracted my attention my attention for several years is the question whether, in a conducting tissue, excitation travels better with or against the direction of an electric current. The experimental difficulties presented in the prosecution of this enquiry are very numerous, the results being complicated by the joint effects of the direction of current on conductivity and of the poles on excitability. As regards the latter, the changes of excitability in the animal nerve under electrotonus have been demonstrated by the well-known experiments of pflüger. In a nerve-and-muscle preparation, the presence of a pole P is shown to induce a variation of excitability of a neighbouring point S. When P is kathode, the excitability of the point S, near it, is enhanced; stimulation of S, previously ineffective, now becomes effective, and the resulting excitation is transmitted to M, causing response of the muscle. Conversely, the application of anode at P causes a depression of excitability of S. Stimulus previously effective now becomes ineffective. In this manner the transmission of excitation may be indirectly modified by the polar variation of excitability of the stimulated point (fig. 1 a ).

scholarly journals EXPERIMENTS ON THE RELATION OF THE INHIBITORY TO THE ACCELERATOR NERVES OF THE HEART

1897 ◽  
Vol 2 (2) ◽  
pp. 151-179 ◽  
Author(s):  
Reid Hunt
Keyword(s):  
Mode Of Action ◽  
Inhibitory Effect ◽  
Relative Strength ◽  
The Other ◽  
Maximal Stimulation ◽  
The One ◽  
Considerable Period ◽  
Minimal Stimulation ◽  
Ventricular Beat ◽  
Stimulation Of

The experiments described in Part IV of this paper show that in whatever manner the problem of the relation of the vagus to the accelerators is approached, whether the accelerators are stimulated during a stimulation of the vagus, or the vagus during a stimulation of the accelerators, or both are stimulated simultaneously, either for a short or for a longer period, the result is the same, viz., the effect upon the rate of the heart is determined entirely by the relative strength of the stimuli applied to the two nerves. If the stimuli are of approximately the same strength, as judged by the effect of stimulating the nerves separately, the rate of the heart is but slightly affected; if the stimulus applied to the vagus is the stronger, the heart is slowed; if it is weaker, the heart is accelerated. In all cases the result of stimulating the two nerves simultaneously is approximately the algebraic sum of the results of stimulating them separately; sometimes the inhibitory effect slightly predominates, but not more frequently than does the accelerator effect. Moreover, the two nerves may be stimulated simultaneously for a considerable period of time without either completely overcoming the effect of the other. Thus as far as their effect upon the rate of the ventricular beat is concerned, the vagus and accelerator nerves seem to be purely antagonistic; the statement that a minimal stimulation of the one can completely overcome a maximal stimulation of the other is undoubtedly incorrect, and the hypotheses as to the mode of action of these nerves upon the heart, based upon this statement, lose their chief support.

PREFERENTIAL RELEASE OF OXYTOCIN FROM THE NEUROHYPOPHYSIS AFTER ELECTRICAL STIMULATION OF THE AFFERENT PATH OF THE MILK-EJECTION REFLEX IN THE BRAIN OF THE GUINEA-PIG

1968 ◽  
Vol 40 (2) ◽  
pp. 205-214 ◽  
Author(s):  
J. S. TINDAL ◽  
G. S. KNAGGS ◽  
A. TURVEY
Keyword(s):  
Blood Pressure ◽  
Electrical Stimulation ◽  
Guinea Pig ◽  
Arterial Blood Pressure ◽  
Pituitary Stalk ◽  
Milk Ejection ◽  
Arterial Blood ◽  
Milk Ejection Reflex ◽  
The Brain ◽  
Stimulation Of

SUMMARY Discrete portions of the afferent path of the milk-ejection reflex have been explored in the brain of the lactating guinea-pig. Both intramammary pressure and arterial blood pressure were recorded to detect release of oxytocin and vasopressin. It was found that the milk-ejection responses which occurred after electrical stimulation of the pathway in the midbrain and hypothalamus were caused by the release of oxytocin without detectable release of vasopressin. A mixture of oxytocin and vasopressin, in the ratio of approximately 3:1, was released only after electrical stimulation of the rostral tuberal region of the hypothalamus adjacent to the pituitary stalk. It is concluded that the afferent path in the brain of the guinea-pig studied is concerned with the preferential release of oxytocin from the neurohypophysis and that it is the pathway of the milk-ejection reflex.

scholarly journals The Promise of Multiwavelength and IFU Observations

2009 ◽  
Vol 5 (S262) ◽  
pp. 217-224
Author(s):  
Robert C. Kennicutt ◽  
Cai-Na Hao ◽  
Benjamin D. Johnson ◽  
Fabian Rosales-Ortega ◽  
Angeles Díaz ◽  
...  
Keyword(s):  
The Other ◽  
Wide Field ◽  
Spatially Resolved ◽  
Multi Wavelength ◽  
The One ◽  
Integral Field ◽  
Field Integral

AbstractMany of the advances of the last decade in this subject have been the result of large spectroscopic surveys of galaxies on the one hand, and multi-wavelength surveys of galaxies on the other. This talk highlights applications that exploit a combination of spectroscopic and multi-wavelength diagnostics. Most applications to date have been based on spatially integrated measurements of galaxies, but the introduction of wide-field integral field spectrometers promises to extend ths approach to spatially-resolved analyses of galaxies.

DETERMINATION OF THE DETAILED HYPOTHALAMIC ROUTE OF THE MILK-EJECTION REFLEX IN THE GUINEA-PIG

1971 ◽  
Vol 50 (1) ◽  
pp. 135-152 ◽  
Author(s):  
J. S. TINDAL ◽  
G. S. KNAGGS
Keyword(s):  
Electrical Stimulation ◽  
Lateral Hypothalamus ◽  
Third Ventricle ◽  
Milk Ejection ◽  
Lateral Direction ◽  
Reflex Pathway ◽  
Oxytocin Release ◽  
Far Lateral ◽  
Milk Ejection Reflex ◽  
Stimulation Of

SUMMARY The effect of various types of surgical damage to the forebrain on the release of oxytocin in response to electrical stimulation of the discrete ascending milk-ejection reflex pathway in the mid-brain was investigated in 99 anaesthetized lactating guinea-pigs. Oxytocin release was measured by comparison of experimental milk-ejection responses with the response to i.v. injection of known amounts of synthetic oxytocin. Removal of the entire telencephalon, including cerebral cortex, hippocampi, amygdalae and forebrain rostral to the hypothalamus, did not affect the subsequent release of oxytocin after electrical stimulation of the pathway in the mid-brain, from which it was concluded that the reflex pathway within the forebrain is entirely diencephalic. Transection of the hypothalamus immediately rostral to the paraventricular (PV) nuclei was without effect, while transection immediately caudal to the PV nuclei blocked the release of oxytocin. Destruction of the PV nuclei by a radiofrequency lesion which spared the supraoptic (SO) nuclei blocked the release of oxytocin. Undercutting both PV nuclei so as to isolate them from the ventral hypothalamus blocked the release of oxytocin. Undercutting the PV nucleus ipsilateral to the stimulated side of the mid-brain blocked the release of oxytocin, while undercutting the contralateral PV nucleus had no effect. The PV nuclei, therefore, lie on the ascending path of the milk-ejection reflex, the SO nuclei do not, and, from the mid-brain forwards, the ascending pathway remains uncrossed. The course of the reflex pathway was traced rostrally from the mesodiencephalic junction by making narrow transverse knife-cuts and determining which cuts reduced or blocked the release of oxytocin after mid-brain stimulation. At this level, the pathway on each side of the brain is represented by separate dorsal and ventral paths and in the present study it was found that the ventral path is more important than the dorsal path in terms of oxytocin release. The ventral path passes forward in the medial forebrain bundle, in the far-lateral hypothalamus, while the dorsal path enters the posterior hypothalamus dorsally in the periventricular region at the top of the third ventricle and impinges on the thalamic reuniens nucleus. Shortly afterwards the dorsal path swings abruptly in the lateral direction to join the ventral path in the lateral hypothalamus. The reunited pathway then moves forward in this position until it is level with the PV nuclei, where it swings dorsomedially to relay with the lateral tip of the ipsilateral PV nucleus, and in doing so intermingles with the descending neurosecretory fibres from this nucleus.

scholarly journals ON THE RELATION OF DIRECT CURRENTS TO CONDENSER DISCHARGES AS STIMULI

1935 ◽  
Vol 18 (5) ◽  
pp. 755-766 ◽  
Author(s):  
H. A. Blair
Keyword(s):  
Differential Equation ◽  
Electrical Stimulation ◽  
The Other ◽  
The One ◽  
Stimulation Of

Data on the electrical stimulation of sciatic-gastrocnemius preparations of the frog by both direct currents and condenser discharges at the same time are discussed in relation to the validity of the differential equation See PDF for Equation where p is the local excitatory process, V the stimulating current or voltage, and K and k are constants. It is concluded that the constant k is the same whether it is derived from the data of the one stimulus or the other when the same fibres are being stimulated.

scholarly journals Exposed Pedagogy: Architecture as (a) Medium (of communication)

2021 ◽  
Author(s):  
◽  
Michael Smith
Keyword(s):  
Public Discourse ◽  
The Other ◽  
Social Implications ◽  
The Public ◽  
The Social ◽  
The One ◽  
Stimulation Of ◽  
Three Components

<p>Architecture schools are often isolated from the profession and the public they serve both pedagogically and physically, and often this is justified. Schools are not typically very public. However, schools could play a much greater role in the stimulation of a public discourse around architecture. The intent of this thesis is to examine how architecture can stimulate that discussion and ultimately how architecture could frame that discourse. The thesis proposes that an architecture school can and should be a vehicle for public discourse by way of framing that discourse on the one hand and overtly stimulating it on the other. Specifically, an architecture school has the capacity to contribute to public discourse through the visual affects of form making and the social implications of that same form. The research is divided into three components that chronicle an argument from contextualisation, through investigation to application.</p>

Suckling-induced release of cholecystokinin into plasma in the lactating rat: effects of abdominal vagotomy and lesions of central pathways concerned with milk ejection

1990 ◽  
Vol 127 (2) ◽  
pp. 257-263 ◽  
Author(s):  
A. Linden ◽  
M. Eriksson ◽  
S. Hansen ◽  
K. Uvnäs-Moberg
Keyword(s):  
Electrical Stimulation ◽  
Plasma Levels ◽  
Vagal Nerve ◽  
Milk Ejection ◽  
Vagal Nerves ◽  
Plasma Cholecystokinin ◽  
Milk Ejection Reflex ◽  
Stimulation Of

ABSTRACT Plasma levels of cholecystokinin were increased in response to suckling in lactating rats. Efferent electrical stimulation of the vagal nerve increased the concentration of cholecystokinin in plasma. Abdominal vagotomy was found to block the suckling-induced release of cholecystokinin. Furthermore, lesions to the lateral midbrain, which disrupt the oxytocin-mediated milk-ejection reflex, were shown to inhibit the increase in plasma cholecystokinin. These results show that the suckling-induced release of cholecystokinin into plasma in lactating rats is dependent upon the vagal nerves and the central neural structures concerned with milk let-down. Journal of Endocrinology (1990) 127, 257–263

THE AFFERENT PATHWAY OF THE MILK-EJECTION REFLEX IN THE MID-BRAIN OF THE GOAT

1972 ◽  
Vol 52 (2) ◽  
pp. 333-341 ◽  
Author(s):  
G. S. KNAGGS ◽  
A. S. McNEILLY ◽  
J. S. TINDAL
Keyword(s):  
Guinea Pig ◽  
Afferent Pathway ◽  
Milk Ejection ◽  
Spinothalamic Tract ◽  
Blood Samples ◽  
Indifferent Electrode ◽  
Oxytocin Release ◽  
Milk Ejection Reflex ◽  
Fuller’S Earth ◽  
Stimulation Of

SUMMARY The position of the pathway for the release of oxytocin in the mid-brain was ascertained by exploration of a transverse stereotaxic plane (A4) in 23 anaesthetized goats. Electrical stimulation was applied between a monopolar electrode and an indifferent electrode in the scalp. Oxytocin release was monitored by simultaneous collection of blood samples during stimulation from a catheter in a jugular vein. The blood samples were extracted by the Sephadex G-25 or fuller's earth method and assayed for oxytocin content on the lactating guinea-pig preparation. Oxytocin release occurred occasionally after stimulation of certain sites in the tectum, central grey and reticular formation. Regular releases of oxytocin, however, were only obtained after stimulation of a pathway which was compact and lay in the lateral tegmentum of the mid-brain in association with the spinothalamic tract. The position of this pathway corresponds to that described previously for the afferent pathway of the milk-ejection reflex in the mid-brain of the guinea-pig and rabbit. In these three species therefore, the impulses concerned in oxytocin release appear to ascend through the mid-brain in the spinothalamic tract.

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