Histology and Ultrastructure of the Esophagus in European Beaver () Displays Features Adapted to Seasonal Changes in Diet.

The European beaver is a herbivorous rodent whose diet changes seasonally, and in winter consists of large quantities of woody plants. It is distinguished among other mammals by a unique organization of the stomach that comprises the cardiogastric gland and by the unusual process of mucus formation in the gastric mucosa. The aim of study was to (i) characterize the structure of the beaver esophagus with particular attention to the mucosal epithelium; (ii) compare the histological structure of the esophagi collected in spring, summer, and winter; (iii) provide preliminary data on the structure of the esophagus in beaver fetuses.

Changes in the Metabolic Profile of Melatonin Synthesis-Related Indoles during Post-Embryonic Development of the Turkey Pineal Organ.

Research on age-dependent changes in pineal activity has been limited almost exclusively to melatonin (MLT). This study determined, for the first time, the alterations occurring in the metabolic profile of MLT synthesis-related indoles during the post-embryonic development period in birds. Turkeys reared under a 12 h light/dark cycle were euthanized at 2 h intervals for 24 h at the ages of 2, 7, 14, and 28 days and 10, 20, 30, and 45 weeks.

Dopamine D2 receptors modulate the cholinergic pause and inhibitory learning.

Cholinergic interneurons (CINs) in the striatum respond to salient stimuli with a multiphasic response, including a pause, in neuronal activity. Slice-physiology experiments have shown the importance of dopamine D2 receptors (D2Rs) in regulating CIN pausing, yet the behavioral significance of the CIN pause and its regulation by dopamine in vivo is still unclear. Here, we show that D2R upregulation in CINs of the nucleus accumbens (NAc) lengthens the pause in CIN activity ex vivo and enlarges a stimulus-evoked decrease in acetylcholine (ACh) levels during behavior.

Embryonic Development of Avian Pineal Secretory Activity-A Lesson from the Goose Pineal Organs in Superfusion Culture.

The embryonic ontogeny of pineal secretory activity in birds has been investigated almost exclusively in chickens. This study aimed to characterize this process in domestic geese. The pineal organs of embryos aged 18-28 days were incubated in superfusion culture under different light conditions for 4-5 days and treated with norepinephrine (NE).