Diazepam also decreases prolactin release in rats. Mechanism of action
Benzodiazepines are positive allosteric modulators of the GABA type A receptors (GABAA). The GABAA receptors are ligand-gated chloride-selective ion channels that are activated by GABA, the major inhibitory neurotransmitter in the brain. Binding of benzodiazepines to this receptor complex promotes the binding of GABA, which in turn increases the total conduction of chloride ions across the neuronal cell membrane. This increased chloride ion influx hyperpolarizes the neurons membrane potential. As a result, the difference between resting potential and threshold potential is increased and firing is less likely. As a result, the arousal of the cortical and limbic systems in the central nervous system is reduced.The GABAA receptor is a heteromer composed of five subunits, the most common ones being two αs, two βs, and one γ (α2β2γ). For each subunit, many subtypes exist (α1–6, β1–3, and γ1–3). GABAA receptors containing the α1 subunit mediate the sedative, the anterograde amnesic, and partly the anticonvulsive effects of diazepam. GABAA receptors containing α2 mediate the anxiolytic actions and to a large degree the myorelaxant effects. GABAA receptors containing α3 and α5 also contribute to benzodiazepines myorelaxant actions, whereas GABAA receptors comprising the α5 subunit were shown to modulate the temporal and spatial memory effects of benzodiazepines. Diazepam is not the only drug to target these GABAA receptors. Drugs such as flumazenil also bind to GABAA to induce their effects.Diazepam appears to act on areas of the limbic system, thalamus, and hypothalamus, inducing anxiolytic effects.
Liver biopsy is the gold standard for determining the extent of hepatic fibrosis and assessing for the presence of cirrhosis.A1AT deficiency remains undiagnosed in many patients. Patients are usually labeled as having COPD without an underlying cause. It is estimated that about 1% of all COPD patients actually have an A1AT deficiency. Testing is recommended in those with COPD, unexplained liver disease, unexplained bronchiectasis, granulomatosis with polyangiitis or necrotizing panniculitis. American guidelines recommend that all people with COPD are tested, whereas British guidelines recommend this only in people who develop COPD at a young age with a limited smoking history or with a family history. The initial test performed is serum A1AT level. A low level of A1AT confirms the diagnosis and further assessment with A1AT protein phenotyping and A1AT genotyping should be carried out subsequently.As protein electrophoresis does not completely distinguish between A1AT and other minor proteins at the alpha-1 position (agarose gel), antitrypsin can be more directly and specifically measured using a nephelometric or immunoturbidimetric method. Thus, protein electrophoresis is useful for screening and identifying individuals likely to have a deficiency. A1AT is further analyzed by isoelectric focusing (IEF) in the pH range 4.5-5.5, where the protein migrates in a gel according to its isoelectric point or charge in a pH gradient. Normal A1AT is termed M, as it migrates toward the center of such an IEF gel. Other variants are less functional and are termed A-L and N-Z, dependent on whether they run proximal or distal to the M band.