FIGURE 2.

In situ hybridization of 5-HTR1A in the P1 chick brainstems. Digoxigenin-labeled RNA antisense (A–D) and sense (A’–D’) 5-HTR1A probes were used for in situ hybridization in coronal sections of P1 chick brains. To evaluate the expression patterns of 5-HTR1A, sections of four chicks were analyzed, and representative images of two chick brain sections are shown. (B,B’) Magnified views of brain areas in the box in panel (A”) are shown. (A”–D”) Diagrams of coronal sections are shown in the rightmost panels. The levels of the sections (A 2.6, A 1.8, and A 1.4) are in accordance with those mentioned in Kuenzel and Masson’s chick atlas (Kuenzel and Masson, 1988). BCS, brachium colliculi superiors; CS, nucleus centralis superior; FLM, fasciculus longitudinalis medialis; GCt, griseum centrale; ICo, nucleus intercolicularis; LLi, nucleus ventralis lemnisci lateralis; nIV, nucleus nervi trochlearis; OMN, oculomotor nucleus; Pap, nucleus papillioformis; RPO, nucleus reticularis pontis oralis; SGC, stratum griseum centrale; TD, nucleus tegmenti dorsalis; VT, ventriculus tecti mesencephali; P1, post-hatch day 1. Scale bars = 2.5 mm (A,D,A’,D’) and 1 mm (B,C,B’,C’).