N2 nicotinic receptors are found in the brain, plus the autonomic and parasympathetic nervous systems [1]. Different subunits make up these two types of nicotinic receptor, which is why we consider them separately. Muscarinic receptors have a different mechanism of action.
Your body weight can regularly fluctuate, but the persistent, unintentional loss of more than 5% of your weight over 6 to 12 months is usually a cause for concern. You should pay particular attention if you experience other symptoms, such as tiredness, loss of appetite and a change in your toilet habits.
Unintentional weight loss is normally the result of an underlying chronic medical condition. However, short-term illnesses such as influenza or the common cold can also cause weight loss due to abdominal discomfort. Common causes of unintentional weight loss include: 1  depression. 2  diarrhea. 3  oral ulcers.