Differential activation of the 5-hydroxytryptamine-containing neurons of the midbrain raphe of the rat in response to randomly presented inescapable sound.
Estimates of 5-hydroxytryptamine (5-HT) turnover in response to 30 min of inescapable, randomly presented, loud sound (sound stress) were obtained for regions of rat brain containing 5-HT perikarya by means of 5-hydroxytryptophan (5-HTP) accumulation after administration of an inhibitor of aromatic amino acid decarboxylase (100 mg/kg i.p., m-hydroxybenzylhydrazine, NSD 1015). Sound stress increased 5-HTP accumulation in the median raphe nucleus (MRN) twofold over that from sham-stressed controls, but did not change 5-HTP accumulation significantly in dorsal raphe nucleus (DRN) or hindbrain. These findings indicate that the 5-HT perikarya of the MRN but not those of the DRN or hindbrain are activated by sound stress, thus, provide further evidence for a functional distinction between the 5-HT neurons of these two midbrain nuclei.
Dilts
R P
RP
Department of Physiology, Medical College of Virginia, Virginia Commonwealth University, Richmond 23298-0551, USA.
Boadle-Biber
M C
MC
D006916:5-Hydroxytryptophan / Q000378:metabolism; D000161:Acoustic Stimulation; D000818:Animals; D065105:Aromatic Amino Acid Decarboxylase Inhibitors; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006834:Hydrazines / Q000494:pharmacology; D008297:Male; D009434:Neural Pathways / Q000166:cytology / Q000502:physiology; D009474:Neurons / Q000378:metabolism*; D011897:Random Allocation; D011903:Raphe Nuclei / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000378:metabolism*; D013315:Stress, Psychological / Q000378:metabolism*
D065105:Aromatic Amino Acid Decarboxylase Inhibitors; D004791:Enzyme Inhibitors; D006834:Hydrazines; D012701:Serotonin; C004297:3-hydroxybenzylhydrazine; D006916:5-Hydroxytryptophan