0
Get Alert
Please Wait... Processing your request... Please Wait.
You must sign in to sign-up for alerts.

Please confirm that your email address is correct, so you can successfully receive this alert.

1
Letter to the Editor   |    
Dr. Yasuno and Colleagues Reply
FUMIHIKO YASUNO, M.D., Ph.D.; TETSUYA SUHARA, M.D., Ph.D.; TAKASHI NAKAYAMA, M.D.; TETSUYA ICHIMIYA, M.D., Ph.D.; AKIHIRO TAKANO, M.D., Ph.D.; TOMOMICHI ANDO, M.D.; MAKOTO INOUE, M.D., Ph.D.; JUN MAEDA, M.S.; KAZUTOSHI SUZUKI, Ph.D.; YOSHIRO OKUBO, M.D., Ph.D.
Am J Psychiatry 2004;161:1505-a-1506. doi:10.1176/appi.ajp.161.8.1505-a

To the Editor: My colleagues and I thank Drs. Sumiyoshi and Meltzer for commenting on our study, and we agree with them when they say that our results extend their previous observations with schizophrenic patients (Sumiyoshi et al., 2001). They comment that we failed to mention the discrepant results regarding the effect of the lower dose (30 mg/day) of tandospirone on memory performance, i.e., the facilitative influence in their studies versus the partially inhibitory effects in our study reported in the Journal. However, the patients in their study received tandospirone, 10 mg t.i.d., while the subjects in our study received the 30 mg of tandospirone at one time. Because of this difference, we cannot directly compare their results with ours. Previous studies have shown that the half-life of the plasma concentration of tandospirone was relatively short (1.2–1.4 hours), and the effect of the accumulation of this drug is reported to be negligible when the subjects received 10 mg t.i.d. of tandospirone for more than 3 months (1, 2). From this point of view, the plasma concentration of tandospirone in their studies might have been lower than that of ours.

They pointed out that the apparent difference between the two studies is that we studied the acute effect of tandospirone while they assessed its long-term effect over 6 weeks. They suggested that some adaptive changes in 5-HT1A receptor function occurs during prolonged administration of the drug, leading to an altered response of 5-HT1A receptors to intrinsic 5-HT or the 5-HT1A agonist. As to this point, we agree with their notion, and future work must address the details of the long-term effect of tandospirone on the adaptive changes in 5-HT1A receptor function.

They also claimed that the difference was that our study used normal subjects, while their studies were concerned with patients with schizophrenia. In our recent study (3), we measured the availability of 5-HT1A receptors in patients with schizophrenia and normal comparison subjects using positron emission tomography with [11C]WAY-100635. With regard to the binding of 5-HT1A receptors in the hippocampus, we found no significant difference between patients and comparison subjects (3). But this result did not contradict the different effect of tandospirone on the explicit memory function between normal subjects and patients. Cellular localization of 5-HT1A receptors has been demonstrated on both cholinergic and glutamatergic neurons (4, 5), and the effect of tandospirone on memory function might be affected by disease change of these neurotransmitter systems. The interaction between 5-HT1A receptors and the disease change of several neurotransmitter systems needs to be considered when assessing the effect of tandospirone on memory function in patients with schizophrenia and other psychiatric disorders.

In conclusion, we share the opinion of Drs. Sumiyoshi and Meltzer that agents that activate presynaptic 5-HT1A receptors, as well as drugs that work as antagonists at postsynaptic 5-HT1A receptors, may be of value in treating some of the cognitive deficits in schizophrenia and possibly other psychiatric disorders as well.

Nakashima M, Kanamaru M: [Phase 1 study of a new non-benzodiazepine antianxiety drug, SM-3997.] Kiso to Rinsho  1992; 26:4143–4165 (Japanese)
 
Tsutsui S, Saito T, Katsura T: [Clinical evaluation of a new psychotropic drug, tandospirone (SM-3997): long-term treatment on psychosomatic disease and neurosis.] Kiso to Rinsho  1992; 26:114–125 (Japanese)
 
Yasuno F, Suhara T, Ichimiya T, Takano A, Ando T, Okubo Y: Decreased 5-HT1A receptor binding in amygdala of schizophrenia. Biol Psychiatry  2004; 55:439–444
[PubMed]
[CrossRef]
 
Steckler T, Sahgal A: The role of serotonergic-cholinergic interactions in the mediation of cognitive behaviour. Behav Brain Res  1995; 67:165–199
[PubMed]
[CrossRef]
 
Boast C, Nartolomeo AC, Morris H, Moyer JA: 5-HT antagonists attenuate MK801-impaired radial arm maze performance in rats. Neurobiol Learn Mem  1999; 71:259–271
[PubMed]
[CrossRef]
 
+

References

Nakashima M, Kanamaru M: [Phase 1 study of a new non-benzodiazepine antianxiety drug, SM-3997.] Kiso to Rinsho  1992; 26:4143–4165 (Japanese)
 
Tsutsui S, Saito T, Katsura T: [Clinical evaluation of a new psychotropic drug, tandospirone (SM-3997): long-term treatment on psychosomatic disease and neurosis.] Kiso to Rinsho  1992; 26:114–125 (Japanese)
 
Yasuno F, Suhara T, Ichimiya T, Takano A, Ando T, Okubo Y: Decreased 5-HT1A receptor binding in amygdala of schizophrenia. Biol Psychiatry  2004; 55:439–444
[PubMed]
[CrossRef]
 
Steckler T, Sahgal A: The role of serotonergic-cholinergic interactions in the mediation of cognitive behaviour. Behav Brain Res  1995; 67:165–199
[PubMed]
[CrossRef]
 
Boast C, Nartolomeo AC, Morris H, Moyer JA: 5-HT antagonists attenuate MK801-impaired radial arm maze performance in rats. Neurobiol Learn Mem  1999; 71:259–271
[PubMed]
[CrossRef]
 
+
+

CME Activity

There is currently no quiz available for this resource. Please click here to go to the CME page to find another.
Submit a Comments
Please read the other comments before you post yours. Contributors must reveal any conflict of interest.
Comments are moderated and will appear on the site at the discertion of APA editorial staff.

* = Required Field
(if multiple authors, separate names by comma)
Example: John Doe



Web of Science® Times Cited: 1

Related Content
Books
The American Psychiatric Publishing Textbook of Psychopharmacology, 4th Edition > Chapter 1.  >
The American Psychiatric Publishing Textbook of Psychopharmacology, 4th Edition > Chapter 47.  >
The American Psychiatric Publishing Textbook of Psychopharmacology, 4th Edition > Chapter 45.  >
Textbook of Traumatic Brain Injury, 2nd Edition > Chapter 17.  >
The American Psychiatric Publishing Textbook of Psychopharmacology, 4th Edition > Chapter 51.  >
Topic Collections
Psychiatric News
Read more at Psychiatric News >>
APA Guidelines
PubMed Articles