Anatomy and Function of the Hypothalamus

The hypothalamus is a small but important area of the brain formed by various nucleus and nervous fibers. Through its neuronal connections, it is involved in many complex functions of the organism such as vegetative system control, homeostasis of the organism, thermoregulation, and also in adjusting the emotional behavior. The hypothalamus is involved in different daily activities like eating or drinking, in the control of the body’s temperature and energy maintenance, and in the process of memorizing. It also modulates the endocrine system through its connections with the pituitary gland. Precise anatomical description along with a correct characterization of the component structures is essential for understanding its functions

Delayed rectifier potassium current in undiseased human ventricular myocytes

Objective: The purpose of the study was to investigate the properties of the delayed rectifier potassium current (I-K) in myocytes isolated from undiseased human left ventricles. Methods: The whole-cell configuration of the patch-clamp technique was applied in 28 left ventricular myocytes from 13 hearts at 35 degrees C. Results: An E-4031 sensitive tail current identified the rapid component of I-K (I-Kr) in the myocytes, but there was no evidence for an E-4031 insensitive slow component of I-K (I-Kb). When nifedipine (5 mu M) was used to block the inward calcium current (I-Ca), I-Kr activation was fast (tau=31.0+/-7.4 ms, at +30 mV, n=5) and deactivation kinetics were biexponential and relatively slow (tau(1) =600.0+/-53.9 ms and tau(2)-6792.2+/-875.7 ms, at -40 mV, n=7). Application of CdCl2 (250 mu M) to block I-Ca altered the voltage dependence of the I-Kr considerably, slowing its activation (tau=657.1+/-109.1 ms, at +30 mv n=5) and accelerating its deactivation ( tau=104.0+/-18.5 ms, at -40 mV, n=8). Conclusions: In undiseased human ventricle at 35 degrees C I-Kr exists having fast activation and slow deactivation kinetics; however, there was no evidence found for an expressed I-Ks. I-Kr probably plays an important role in the frequency dependent modulation of repolarization in undiseased human ventricle, and is a target for many Class III antiarrhythmic drugs

Noninvasive Evaluation of Microcirculation under Normal and Pathological Conditions Using Contrast-Enhanced Ultrasonography (CEUS)

The present chapter highlights the most important information about microcirculation and its evaluation using contrast-enhanced ultrasonography (CEUS). In the beginning it outlines some general considerations about microcirculation, together with its morphological and physiological particularities under normal and pathological circumstances. The ultrasonographic (US) evaluation of vascularity is based on the Doppler technique and the harmonic technique using contrast agents. Then it presents briefly the Doppler ultrasound (DUS) and discusses its most important current and emerging indications. CEUS is presented extensively, covering the fundamentals of sonographic contrast agents, harmonic imaging and quantification techniques. A special focus is placed not only on the current and emerging indications of CEUS but also on the advantages and limitations of the method. This chapter also incorporates information about experimental CEUS applications and future perspectives. CEUS is the recommended US method for the characterization of microcirculation. The results of the examination are displayed in real-time, under the eyes of the examiner, while the quantitative assessment of the contrast agent kinetics parameters is easy to perform. This method allows a precise definition of the healthy or pathologic state of an organ and the follow-up of treatment response