Moreover, a reduction of the tyrosine hydroxylase (Th) mRNA level, the rate-limiting enzyme in catecholamine synthesis, was detected in the whole pons of MECP2-null male as well as in adult heterozygous (MECP2+/-) female mice. Using immunoquantitative techniques, a decrease of Th protein staining level, number of locus coeruleus TH-expressing neurons and density of dendritic arborization surrounding the structure was shown in symptomatic MeCP2-deficient mice. However, locus coeruleus cells are not dying, but are more likely losing their fully mature phenotype, since no apoptotic neurons in the pons were detected.Researchers have concluded that "Because these neurons are a pivotal source of norepinephrine throughout the brainstem and forebrain and are involved in the regulation of diverse functions disrupted in Rett syndrome, such as respiration and cognition, we hypothesize that the locus coeruleus is a critical site at which loss of MECP2 results in CNS dysfunction." The restoration of normal locus coeruleus function may therefore be of potential therapeutic value in the treatment of Rett syndrome. Midbrain dopaminergic disturbances
The majority of dopamine in the mammalian brain is synthesized by nuclei located in the mesencephalon. The substantia nigra pars compacta (SNpc), the ventral tegmental area (VTA) and the retrorubral field (RRF) contains dopaminergic neurons expressing tyrosine hydroxylase (Th, i.e. the rate-limiting enzyme in catecholamine synthesis).The nigro-striatal pathway originates from SNpc and irradiate its principal rostral target, the Caudate-Putamen (CPu) through the median forebrain bundle (MFB).
Ethinylestradiol/norethisterone (EE/NET), or ethinylestradiol/norethindrone, is a combination birth control pill which contains ethinylestradiol (EE), an estrogen and norethisterone (NET), a progestin. It is used for birth control, symptoms of menstruation, endometriosis, and menopausal symptoms. Other uses include acne. It is taken by mouth. Some preparations of EE/NET additionally contain an iron supplement in the form of ferrous fumarate.Side effects can include nausea, headache, blood clots, breast pain, depression, and liver problems. Use is not recommended during pregnancy, the initial three weeks after childbirth, and in those at high risk of blood clots. It, however, may be started immediately after a miscarriage or abortion. Smoking while using combined birth control pills is not recommended. It works by stopping ovulation, making the uterus not suitable for implantation, and making the mucus at the opening to the cervix thick.This combination pill was approved for medical use in the United States in 1964. It is on the World Health Organizations List of Essential Medicines. It is available as a generic medication. It is marketed under a large number of brand names. In 2020, it was the 45th most commonly prescribed medication in the United States, with more than 14 million prescriptions. See also
Mestranol/norethisterone
Oral contraceptive formulations
List of combined sex-hormonal preparations


== References ==