2. Behavioral Biology TALKS - Deutsche Zoologische Gesellschaft

unning wheels might be considered as environmental enrichment that stimulates
locomotor activity in captive Djungarian hamsters, 2) already small daily amounts of
exercise seem to be sufficient to dampen short-day acclimation of body weight, 3)
the gonadal axis needs higher amounts of regular exercise for stimulation resulting in
pro-gonadal effects.
����188 Jaim Sivan
Seasonal variations of the sexual segment of the kidney in the Saharan Sand Viper,
Cerastes vipera (Viperidae)
Author: Jaim Sivan 1
Affiliation: 1 Achva Academic College, Shikmim, Israel
The reptilian nephric sexual segment of the kidney (SSK) is lying between the distal
and the collecting tubules of the nephron. The lumen of SSK tubules are surrounded
by one or more layers of elongated cells containing cytoplasmic filaments and with
other cytological characteristics of smooth muscle cells. The SSK cycle is related to
the cyclic activity of the testes. The pre-terminal and terminal parts of the renal
tubules (sexual segment) develop hypertrophy in males when spermatogenetic
activity is observed. These segments are not developed in females and in immature
males and its morphology varies from species to species. In Cerastes vipera testes, an
increase in spermatogenesis occurs in spring and autumn with an inactive period in
spermatozoa production intercalated in June until the beginning of July. In this study
we examine the seasonal variations of the sexual segment of the kidney related to
the cyclic activity of the testes in Cerastes vipera. For light microscopy observation of
tubular diameter and cell height, semi-thick sections were prepared from samples
embedded in epoxy resin material and stained with toluidine blue. As expected,
hypertrophy in the SSK according to the spermatogenic cycle of the testes was found
but they do not precisely coincide with testes values. We have found maximum
hypertrophy in the SSK in the fall (October) and minimum hypertrophy in the summer
(July) when testes values are at a maximum in spring and a minimum in June. We
conclude that SSK secretion have possibly an important role in conservation of sperm
mostly during periods of non-reproductive activity, during hibernation until
copulation in spring (May).
Keywords: Cerastes vipera, reptilian nephric sexual segment of the kidney
����189 Wolf-Michael Weber
Suppressing sodium hyperabsorption in cystic fibrosis using ENaC specific siRNA
Authors: Wolf-Michael Weber 1 , Katja Sobczak 1 , Ken Clark 2 , Steven Hughes 2
Affiliation: 1 Institute of Animal Physiology, WWU Münster; 2 Therapeutic
Oligonucleotide Discovery Performance Unit & Respiratory Therapeutic Area
Unit, GlaxoSmithKline; Stevenage, United Kingdom
The inherited disease cystic fibrosis is characterized by an ion transport imbalance,
principally caused by a defective chloride secretion mediated by a mutated cystic
fibrosis transmembrane conductance regulator (CFTR) and excessively increased Na+absorption
via the amiloride-sensitive epithelial Na+ channel (ENaC). To circumvent
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