Differential sensitivity of tachykinin vs. enkephalin gene expression in the posterior striatum in response to acute p-chloroamphetamine treatment during postnatal development

The acute effects of the monoamine releaser p-chloroamphetamine (pCA, 10 mg/kg, i.p.) on preprotachykinin (PPT) and preproenkephalin (PPE) mRNA expression in the anterior (A-STR) vs. posterior (P-STR) striatum were studied in rodents at postnatal days (PND) 10, 21 and 35. Northern analysis 4 h post-injection yielded no significant mRNA changes within the A-STR of any pCA group. However, significant increases (80-200% of saline control) in PPT mRNA levels occurred within the P-STR at all three postnatal ages. Interestingly, pCA did not increase PPE mRNA levels within the P-STR until PND 35 (150% of saline control). Such observation suggests that tachykinin neurons of the P-STR achieve an earlier monoamine-responsive signal transduction linkage to gene regulation as compared to enkephalin neurons. Given its predominance in the caudal regions of the striatum, 5-HT neurotransmission at the 5-HT2 receptor is suggested to play a central role in this mechanism. (C) 1999 Published by Elsevier Science B.V. All rights reserved.