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Updated: Jun 18, 2026

Micromanipulation of Gene Expression in the Adult Zebrafish Brain Using Cerebroventricular Microinjection of Morpholino Oligonucleotides
Published on: May 23, 2013
Both zimelidine and clorgyline decrease preprotachykinin mRNA in adult medullary raphe nuclei
L A Riley1, R P Hart, G M Jonakait
1Department of Biological Sciences, Rutgers University, Newark, New Jersey 07102 USA.
Abstract:
Neurons of the medullary raphe nuclei contain multiple neurotransmitters including the monoamine neurotransmitter serotonin (5-HT) and the tachykinin substance P (SP). Previously, we showed that inhibition of serotonin synthesis increased levels of mRNA coding for preprotachykinin (PPT), the prohormone precursor of SP (P. D. Walker et al., 1990, Mol. Brain Res. 8: 113-119). To determine whether augmented serotonin transmission would have the predictably opposite effect, we have examined the effects of a 5-HT uptake blocker (zimelidine) and a monoamine oxidase inhibitor (clorgyline) on levels of PPT mRNA. We looked also at the effect of zimelidine and clorgyline on levels of ventral spinal cord substance P-like immunoreactivity (SP-LI) of the same animals. Both zimelidine and clorgyline decreased levels of PPT mRNA in medullary raphe neurons and SP-LI in the ventral spinal cord. The effect on message was transient with levels returning to control by 14 days of drug treatment. These results show that increases in synaptic 5-HT cause transient decreases in PPT mRNA and SP-LI.
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