Stop using Cialis and get emergency medical help if you have: erection is painful or lasts longer than 4 hours (prolonged erection can damage the penis); vision changes or sudden vision loss; or. heart attack symptoms - chest pain or pressure, pain spreading to your jaw or shoulder, nausea, sweating.
For example, we now know that several areas in the brainstem and hypothalamus promote wakefulness by sending arousal signals to the cerebral cortex, the brainâs largest region. These signals come in the form of chemicals called neurotransmitters. When neurons in the arousal areas are active, the cortex remains activated and we stay awake. One area of the brain that promotes arousal is the tuberomammillary nucleus (TMN). Here, neurons release histamine as one of their neurotransmitters. Interestingly, many  anti-histamine  medicines block this arousing signal and cause sleepiness.
The present study specifically investigated the neural correlates of sexual arousal in young healthy males. Of significant interest for future studies is how these activations might change as a function of age, and how male and female brain activations might differ.