If you need eye drops for dry eyes â known as artificial tears â choose a brand without the preservative benzalkonium chloride, which can cause irritation, says Andrew Lotery, professor of ophthalmology at the University of Southampton. âYou tend to find it in eye drops that come in bottles,â he says.
Endorphins are natural opium-like hormones that are produced by the pituitary gland and the hypothalamus of your body. Endorphins act on your brain's opiate receptors to block their ability to receive pain messages from the sensory nerves. This makes you less sensitive to pain. Endorphins also work on your emotions.
Nicotine also increases the level of other neurotransmitters and chemicals that modulate how your brain works. For example, your brain makes more endorphins in response to nicotine. Endorphins are small proteins that are often called the body's natural painkiller. It turns out that the chemical structure of endorphins is very similar to that of heavy-duty synthetic painkillers like morphine.