[Colors and their meaning in culture and psychology--a historical outline and contemporary status of color vision theories].

The mechanism of color perception has intrigued scholars from antiquity. However, the understanding of this phenomena only came with the recognition of the nature of light and visual perception. Ancient concepts, present in science until the Renaissance, were based more on philosophical considerations and theoretical speculations than on anatomical studies and a matter-of-fact assessment of physiological functions of the visual system.

Age-related changes of NA(+), K(+) - ATPase, Ca(+2) - ATPase and Mg(+2) - ATPase activities in rat brain synaptosomes.

Cerebral metabolism of glucose, one of the determinants of tissue ATP level, is crucial for central nervous system function. The activity of P-type pumps, namely Na(+), K(+) - ATPase, Ca(+2) - ATPase and Mg (+2) - ATPase were examined in brain synaptosomes of 5 - day, 3 - month and 18 - month - old rats to determine if changes in enzyme activity related to aging are potentially associated with alterations in glucose homeostasis. Activities of all the ATPases studied in isolated brain synaptosomes were expressed in micromol of Pi liberated from ATP by 1 mg of synaptosome protein during one hour.

Bradykinin-induced alterations of insulin-receptor interaction in rat adipose tissue under normo- and hypothermic conditions.

Background: In this study we compared the effect of bradykinin (BK) on insulin-receptor interaction in rat adipose plasma membranes under normothermic and hypothermic conditions.

Material/methods: Plasma membranes were prepared and purified according to Havrankova and binding assay was performed using (125I) - insulin. The kinetic parameters of the hormone-receptor interaction were analyzed according to Scatchard using the LIGAND - Pc v.

Effect of hypothermia on insulin-receptor interaction in different rat tissues.

Experimental hypothermia caused extensive changes in the number of both classes of insulin receptors in different rat tissues. In the liver, the number of high affinity insulin receptors (HAIRs) decreased by 50% (from 25.3 to 12.

Age dependent changes of insulin receptors in rat tissues.

Aging is associated with insulin resistance but the exact molecular mechanism is still unknown. Tissue insulin resistance can be evoked by the decreased sensitivity to insulin, the decreased responsiveness to hormone or both. As the first step in insulin action is its binding to alfa subunits of the receptor we, therefore, studied the insulin binding kinetics in plasma membranes of the liver, heart and skeletal muscle in order to establish whether their ability to bind the hormone is altered with aging.