Confirmation of ObR subtypes in cerebral microvessels and hypothalamus by PCR: lane 1, no-template control; lane 2, microvessels from 7-d-old neonate; lane 3, microvessels from 2-month-old adult; lane 4, hypothalamus from 7-d-old neonate; lane 5, hypothalamus from 2-month-old adult. Note the absence of amplification of ObRd, in contrast to the positive products of ObRa, ObRb, ObRc, and ObRe. β-Actin was amplified as an internal control.