Cholinergic and serotonergic activities are required in triggering conditioned NK cell response.

The purpose of the study was to examine the importance of the cholinergic system in triggering the conditioned NK cell response. The fact that serotonergic system can modulate cholinergic functions suggested that it might be involved in conditioned NK cell response. To evaluate the potential pathways, cholinergic and serotonergic antagonists were applied centrally at either the conditioned association or recall stage, to interfere with the conditioned NK cell response. The results showed that both the cholinergic and serotonergic systems were necessary for eliciting the conditioned enhancement of NK cell activity. Involvements of the two systems were found to be critical for establishing the conditioned association and recall of the conditioned response. The blocks are believed to be receptor mediated. The receptors identified to be involved in the regulation of the conditioned NK cell response were: M(1), M(2) and M(3) muscarinic; nicotinic; 5 HT(1) and 5 HT(2) receptors.