DIFFERENTIAL EXPRESSION OF 5 SOMATOSTATIN RECEPTOR SUBTYPES, SSTR1-5,IN THE CNS AND PERIPHERAL TISSUE

Somatostatin regulates endocrine and exocrine secretion, acts as a neu rotransmitter/neuro-modulator and possesses antiproliferative properti es. These diverse physiological effects are mediated by G-protein coup led receptors of which at least five subtypes have been cloned (SSTR1- 5). Here, we have investigated the tissue distribution pattern of mRNA s encoding the five SRIF receptor subtypes in the adult rat by RT-PCR analysis and in situ hybridization histochemistry. Ah five receptor su btypes were found to be expressed simultaneously in brain and pituitar y by RT-PCR. Besides, the in situ hybridization results clearly show a distinct but overlapping expression pattern of SSTR1-5 mRNA in the ce ntral nervous system as was found by RT-PCR for the periphery. Such di stinct SRIF receptor expression may contribute to the selective biolog ical functions of the receptor subtypes.