Additionally, when activated, adrenoceptor subtypes 2A and 2B have been shown to have vasoconstrictive effects on the cardiovascular system in addition to their sedative and antinociceptive effects. These chemicals have an effect on dopaminergic neurotransmission, hypothermia, and a wide range of behavioural reactions in the body, as well as on metabolism, among other things. Neuronal activity can also be decreased by antagonising beta-adrenergic receptors, which stimulate potassium ion channels and hence impede neurogenesis. It is believed that this will diminish brain excitability, particularly in the locus cerulean, by inhibiting noradrenaline (norepinephrine) release. The locus cerulean has been linked to the symptoms of withdrawal associated with CNS depressants, as well as anxiety and sleep difficulties, according to research. Noradrenergic activity is mostly concentrated in the locus cerulean region of the brain (e.g. opioids).