Reticular stimulation evokes suppression of CA1 synaptic responses and generation of theta through separate mechanisms

• DOI: 10.1111/j.0953-816x.2003.03127.x
• Publication Date: 2004-01-16T08:36:25Z
• Authors: Fengli Jiang; Sanjay Khanna
• Keywords: Pyramidal cell; Antidromic; Reticular connective tissue

Abstract The induction of hippocampal theta by reticular stimulation involves a relay to the hippocampus via posterior hypothalamic–supramammillary region and then medial septum. Interestingly, sensory‐ or behaviour‐induced is accompanied suppression field CA1 synaptic responses. In present study, performed on anaesthetized rats, we observed that also induced pyramidal cell population spike corresponding dendritic excitatory postsynaptic potential evoked CA3 stimulation. This was at intensity below threshold for generation maximal intensities theta. frequency amplitude waves, contrast, increased further with increasing voltage. Neural inactivation microinjection local anaesthetic procaine (20% w/v, 0.1–0.2 µL) inhibitory ligand gamma aminobutyric acid (0.8 m , 0.5 in hypothalamic regions, especially ipsilateral supramammillary region, septum attenuated both excitability generation. However, effects were not always parallel. Furthermore, effect reticularly elicited from relatively fewer sites hypothalamus as compared activation. These results suggest evokes an inhibition (i) mediated, least part, septal but (ii) separate neural pathway