Physiology Commons^™

The Effects Of Carboxyl-Group Specific Modification And Triiodo-L-Thyronine On Cardiac Sodium Channels, Samuel C. Dudley

Theses and Dissertations

The patch clamp method was used to evaluate the effects of 3,5,3'-triiodo-L-thyronine (T₃) and carboxyl modification on adult rabbit ventricular Na⁺ channels. In contrast to TTX-sensitive Na⁺ channels, Ca²⁺ block of cardiac Na⁺ channels was not prevented by selective carboxyl modification by trimethyloxonium (TMO) or water soluble carbodiimide (WSC). In 2 mM Ca²⁺, TMO-treated patches exhibited 3 discrete conductance (γ_Na) levels. An abbreviation of mean open time (MOT) accompanied each decrease in γ_Na. The effects on channel gating of elevating external Ca²⁺ differed from those of TMO …

Role Of Newly Synthesized Steroid Hormone Antagonists In Adrenocortico-Steroid Hormone-Induced Hypertension, Justicia Opoku-Edusei

Theses and Dissertations

Excess adrenocorticosteroid hormones such as glucocorticoids and mineralocorticoids is well known to induce hypertension in several animal species as well as in humans. Therefore, the development of potent and specific glucocorticoid and mineralocorticoid antagonists with antihypertensive effects is clinically necessary. steroid hormone antagonists being used therapeutically present serious endocrinology side effects such as the widely used antimineralocorticoid, spironolactone. The antiglucocorticoids available so far have been active only in vitro or only weakly in viva. Recently, three new exciting adrenocorticosteroid hormone antagonists have been synthesized. RU 486 is a potent antiglucocorticoid (and antiprogesterone with potential as an abortifacient), RU 26752 and …

Effects Of Hematocrit Variations On Microcirculatory Hemodynamics And Oxygen Transport In Hamster Striated Muscle, Lih Kuo

Theses and Dissertations

Experiments were performed to investigate the influence of isovolemic hemodilution and hemoconcentration on microcirculatory hemodynamics and oxygen transport in the hamster cheek pouch retractor muscle. Measurements of red blood cell velocity, microvessel hematocrit, vessel diameter, segment length (L), hemoglobin oxygen saturation (SO₂) and longitudinal SO₂ gradient (ΔSO₂/L) were made in four arteriolar branching orders before and after isovolemic exchange with plasma (hemodilution) or packed red blood cells (hemoconcentration).

In the study of hemodilution, systemic hematocrit was reduced from 52 to 33% in 23 hamsters. This degree of hemodilution resulted in an average decrease in microcirculatory …

Tissue Chromium Levels :|Bautopsy Study In Diabetic And Non-Diabetic American (Pima) Indians, Leslie O. Hansen

Theses and Dissertations

Tissues (liver, spleen, pancreas, and aorta) and hair taken at autopsy from diabetic and non-diabetic southwestern Indians (mainly Pima) were analyzed for chromium (Cr) using flameless atomic absorption spectrophotometry. The Cr levels in both tissues and hair from diabetic subjects were consistently lower than in those from non-diabetic individuals. There were so few individuals in each group that it was not possible to accurately correlate a given tissue either with any other tissues or hair.

Activation Of The Gamma Motor System In The Cat Following Selective Stimulation Of The Motor Cortex And The Pyramidal Tract, James Elliott Forbes

Theses and Dissertations

Until the mid to late 1800's, the cerebral hemispheres were considered to be only the sites of mentation and intellectual activity. On the basis of his observations of epileptic patients, HughIings Jackson (cited from Walshe, l935a) theorized that the cerebral hemispheres were also sites of motor control and sensory experience. The electrical excitability of the cerebrum was first demonstrated by Fritsch and Hitzig in 1870. Since then the motor representation of the various muscles has been mapped out and the types of movement in response to stimulation of the motor cortex and the pyramidal tract have been thoroughly studied.

Mammalian …

Modulation Of Cortical And Pyramidal Tract Induced Motor Responses By Electrical Stimulation Of The Basal Ganglia, Roberta Ann Newton

Theses and Dissertations

Since the early 1800's, the basal ganglia have been recognized as an extrapyramidal subcortical motor area. Much of the knowledge of basal ganglia involvement in movement has been obtained through clinical symptomology. Consideration of the basal ganglia as a pure inhibitory influence upon motor regulation was a concept generated by early researchers (24,57,58). In spite of the fact that the basal ganglia was considered an inhibitory center, it was known that the basal ganglia produced fore limb flexion or contraversive head ‘turning. At the present, both facilitatory and inhibitory influences upon motor activity have been demonstrated (50). Physiological mechanisms underlying …

Glycogen Levels In Cardiac And Skeletal Muscle Of Rats Recovering From Exercise, Walter Talley Judd

Theses and Dissertations

In seeking answers to questions about how the human body functions under stressful situations, scientists, coaches, doctors, and athletes in general have all wondered about the role of exercise in the maintenance of good health. Good cardiovascular health, especially, is sought ardently, as it appears to be a major key to overall body fitness. Good cardiovascular health appears to go hand-in-hand with proper diet, proper rest, and proper exercise (1, 2).

The exercise phenomenon has attracted much attention and poses many questions. Just what is occurring when a person or an animal gets "in shape" by exercising. What bodily changes …

The Effects Of Alcohol On Three Levels Of Complex Human Behavior, Grady Vancil Maraman

Theses and Dissertations

That alcohol affects human behavior has been known for centuries. However, how and why it affects behavior has not been precisely established despite extensive research and study. The inconsistent action of alcohol at different doses on different tissue systems and on different response systems has been well documented (Kalant 1 referenced in 39). The exact sites of action of alcohol in the central nervous system and the relative influence of each of these sites in cognitive and motor behavior are not known. The primary purpose of this experiment was to study the effects of blood alcohol concentrations below 0.100 percent …