Activation of α1-adrenergic receptors produces anorexia and partially mediates the efficacy of appetite suppressants like phenylpropanolamine and amphetamine in the treatment of obesity.[8] Norepinephrine has been shown to decrease cellular excitability in all layers of the temporal cortex, including the primary auditory cortex. In particular, norepinephrine decreases glutamatergic excitatory postsynaptic potentials by the activation of α1-adrenergic receptors.[9] α1-adrenergic receptor subtypes increase inhibition in the olfactory system, suggesting a synaptic mechanism for noradrenergic modulation of olfactory driven behaviors.[10]