TY - JOUR
T1 - Lack of response of serotonergic neurons in the dorsal raphe nucleus of freely moving cats to stressful stimuli
AU - Wilkinson, Lynn O.
AU - Jacobs, Barry L.
N1 - Funding Information:
’ This research was supported by National U.S. Airforce Grant AFOSR 85-0034.
PY - 1988/9
Y1 - 1988/9
N2 - Changes in brain serotonin (5-HT) neurotransmission have been implicated in the mammalian response to stressful stimuli. The purpose of this study was to examine the extracellular single-unit activity of 5-HT neurons in cats exposed to three stressors: loud (100 dB) white noise, restraint, and confrontation with a dog. Serotonergic neurons were recorded in the dorsal raphe nucleus (DRN) and were identified by (i) slow and regular spontaneous activity, (ii) long duration (∼2 ms) waveform, (iii) complete suppression of activity during REM sleep and after systemic administration of 5-methoxy-N-N-dimethyltryptamine (250 μg/kg i.m.), and (iv) histological localization in the DRN. Despite behavioral and physiological evidence that all three manipulations induced a stress response, the maximal firing rate of 5-HT neurons was not significantly different from that observed under unstressed conditions. These data are consistent with previous studies from our laboratory which have indicated that very few manipulations are able to perturb the slow and regular activity of these neurons. In contrast, previous work has shown that the firing rate of noradrenergic neurons in the locus ceruleus is dramatically increased by these stressors. The relative imbalance in the activity of these two neuronal groups observed during stress may affect postsynaptic neuronal processing patterns and have adaptive significance during stressful conditions.
AB - Changes in brain serotonin (5-HT) neurotransmission have been implicated in the mammalian response to stressful stimuli. The purpose of this study was to examine the extracellular single-unit activity of 5-HT neurons in cats exposed to three stressors: loud (100 dB) white noise, restraint, and confrontation with a dog. Serotonergic neurons were recorded in the dorsal raphe nucleus (DRN) and were identified by (i) slow and regular spontaneous activity, (ii) long duration (∼2 ms) waveform, (iii) complete suppression of activity during REM sleep and after systemic administration of 5-methoxy-N-N-dimethyltryptamine (250 μg/kg i.m.), and (iv) histological localization in the DRN. Despite behavioral and physiological evidence that all three manipulations induced a stress response, the maximal firing rate of 5-HT neurons was not significantly different from that observed under unstressed conditions. These data are consistent with previous studies from our laboratory which have indicated that very few manipulations are able to perturb the slow and regular activity of these neurons. In contrast, previous work has shown that the firing rate of noradrenergic neurons in the locus ceruleus is dramatically increased by these stressors. The relative imbalance in the activity of these two neuronal groups observed during stress may affect postsynaptic neuronal processing patterns and have adaptive significance during stressful conditions.
UR - http://www.scopus.com/inward/record.url?scp=0023748624&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0023748624&partnerID=8YFLogxK
U2 - 10.1016/0014-4886(88)90055-6
DO - 10.1016/0014-4886(88)90055-6
M3 - Article
C2 - 3416986
AN - SCOPUS:0023748624
SN - 0014-4886
VL - 101
SP - 445
EP - 457
JO - Experimental Neurology
JF - Experimental Neurology
IS - 3
ER -