The cough reflex has both sensory (afferent) and motor (efferent) components. Pulmonary irritant receptors (cough receptors) in the epithelium of the respiratory tract are sensitive to both mechanical and chemical stimuli. Stimulation of the cough receptors by dust or other foreign particles produces a cough, which is necessary to remove the foreign material from the respiratory tract before it reaches the lungs.
The cough receptors, or rapidly adapting irritant receptors are located mainly on the posterior wall of the trachea, pharynx, and at the main carina, the point where the trachea branches into the main bronchi. The receptors are less abundant in the distal airways, and absent beyond the respiratory bronchioles. When triggered, impulses travel via the internal laryngeal nerve, a branch of the superior laryngeal nerve which stems from the vagus nerve (CN X), to the medulla of the brain. This is the afferent neural pathway. Unlike other areas responsible for involuntary actions like swallowing, there is no clearly identifiable area that can be labeled as the cough center in the brain.
Robitussin DAC (more commonly known as its generic form, Cheratussin DAC) is a narcotic cold medicine, which is available in the United States in a solution. A version without pseudoephedrine is called Robitussin AC. Robitussin products are available over the counter in many countries worldwide, including the Philippines, Thailand, and Nicaragua. Robitussin DAC/AC is available in the United States by prescription only. The manufacturing facility for Robitussin is located on Darbytown Road in Richmond, Virginia at the same location as the prior manufacturer, AH Robins whilst the generic versions are manufactured by Qualitest.
Robitussin was originally produced by AH Robins of Richmond, Virginia. AH Robins was purchased by American Home Products (AHP) in the late 1980s. AHP later changed its name to Wyeth. Wyeth put the manufacturing and marketing of the brand under its Whitehall-Robins Healthcare division. Production was taken over by Pfizer when it acquired Wyeth in 2009.
The cough center of the brain is a region of the brain which controls coughing, located in the medulla oblongata area of the brain. Antitussives and other cough medicines focus their action on the cough center.
The exact location and functionality of the cough center has remained somewhat elusive: while Johannes Peter Müller observed in 1838 that the medulla coordinates the cough reflex, investigating it has been slow because the usual anaesthetics for experimental animals were morphine or opiates, drugs which strongly inhibit cough. In addition, the center likely overlaps with the respiratory rhythm generator networks. It is hence not so much a specific area, but a function within the respiration and reflex networks of the brainstem.