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.
Other causes of unintentional weight loss include: 1  cancer. 2  hyperthyroidism (overactive thyroid gland). 3  hypothyroidism (underactive thyroid gland). 4  abdominal infection.5  gastroenteritis. 6  malnutrition. 7  dementia. 8  Celiac disease.9  HIV/AIDS.ther causes of unintentional weight loss include: 1  cancer. 2  hyperthyroidism (overactive thyroid gland). 3  hypothyroidism (underactive thyroid gland). 4  abdominal infection. 5  gastroenteritis. 6  malnutrition. 7  dementia. 8  Celiac disease. 9  HIV/AIDS.