Somatostatin hyperpolarizes hippocampal pyramidal cells in vitro.

Superfusion onto hippocampal slices of low concentrations of the tetradecapeptide somatostatin (SS), or an SS analogue having CNS activity, reversibly hyperpolarized pyramidal neurons, as revealed by intracellular recording. The hyperpolarizations were accompanied by reductions in spontaneous and evoked spike discharge and in input resistance; the magnitude of the hyperpolarizations was not influenced by 10 mM MgCl2 added to the perfusate to block synaptic transmission.