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.
Depression and anxiety may also cause you to eat more and exercise less than normal. Metabolic or hormonal disruptions, such as hypothyroidism or polycystic ovary syndrome, can cause sudden weight gain and bloating. Cushing's disease can also cause rapid weight gain, especially in the upper body.