Effects of an Agonist of β2 Adrenoreceptors on Reactions of Pyramidal Neurons of Area CA1 of the Rat Hippocampus Modified Due to Blocking of GABAA Receptors

On acute slices of the rat brain, we studied, using extracellular recording of orthodromic field dischargers (OFDs), the effects of an agonist of beta 2 adrenoreceptors, metaproterenol (MPT), and a blocker of GABAA receptors, bicuculline; OFDs were evoked by electrical stimulation of Schaffer collaterals. Isolated application of MPT resulted in some (insignificant) trend toward increase in the intensity of OFDs of pyramidal neurons. Applications of bicuculline induced the appearance of additional spikes (two or even three) in the OFD composition. Upon simultaneous application of MPT and bicuculline, the effect of the latter was preserved and, in some cases, even noticeably enhanced. It is concluded that the agonist of beta 2 adrenoreceptors MPT does not counteract the events switched on after blocking of GABA(A) receptors and, probably, even facilitates the corresponding effects.