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Vagusstoff (literally translated from German as "Vagus Substance") refers to the substance released by stimulation of the vagus nerve which causes a reduction in the heart rate. Discovered in 1921 by physiologist Otto Loewi , vagusstoff was the first confirmation of chemical synaptic transmission and the first neurotransmitter ever discovered.
High levels of prolactin during pregnancy and breastfeeding also increase insulin resistance, increase growth factor levels (IGF-1) and modify lipid metabolism in preparation for breastfeeding. During lactation, prolactin is the main factor maintaining tight junctions of the ductal epithelium and regulating milk production through osmotic balance.
Since a large variety of coat patterns exist within the various cat breeds, the cat is an excellent animal to study the coat genetics of hair growth and coloration. [10] Several genes interact to produce cats' hair color and coat patterns. Different combinations of these genes give different phenotypes.
Fever coat is an effect known in domestic cats, where a pregnant female cat has a fever or is stressed, causing her unborn kittens' fur to develop a silver-type color (silver-grey, cream, or reddish) rather than what the kitten's genetics would normally cause. After birth, over some weeks the silver fur is replaced naturally by fur colors ...
Without ovulation, she may enter interestrus, which is the combined stages of diestrus and anestrus, before reentering estrus. With the induction of ovulation, the female becomes pregnant or undergoes a non-pregnant luteal phase, also known as pseudopregnancy. Cats are polyestrous but experience a seasonal anestrus in autumn and late winter. [19]
The genetic load of organisms and their populations will increase due to the addition of multiple deleterious mutations and decrease the overall reproductive success and fitness. For sexually reproducing populations, studies have shown that single-celled bottlenecks are beneficial for resisting mutation build-up [ citation needed ] .
The mother's milk is very important for the kittens' nutrition and proper growth. This milk transfers antibodies to the kittens, which helps protect them against infectious diseases. [8] As mentioned above, they cannot urinate, so they have a very high requirement for fluids. [9] Kittens open their eyes about seven to ten days after birth.
The koalas require mating in which the presence of ejaculated semen is needed to stimulate the female to produce a LH surge (which would cause ovulation of a follicle). Unlike many other animals, simply being in the presence of a male koala is not enough to induce ovulation itself, nor is vaginal stimulation on its own sufficient to cause ...