Distribution of substance P immunoreactive cell bodies and fibers in cranial sensory and autonomic ganglia of the chick.

Substance P-immunoreactive neurons were demonstrated in chick embryonic and adult trigeminal ganglion and jugular-superior ganglionic complex using FITC-immunohistochemical methods. Both small-size and large ganglion cells exhibited SP immunoreactivity, without apparent changes during embryonic and post-hatching development. SP-positive fibers could be detected in a good number in the sympathetic cranial cervical ganglion, either during embryonic development or in adult chick.

Subsurface cisternae in retinal double cones.

Double cones of tench and goldfish retina are characterized by extensive subsurface cisternae underlying the plasma membranes at the appositional area between the principal and accessory cone. Such a membrane system is absent in double cones of turtle and salamander retina. Measurements on both transverse and longitudinal sections gave a total appositional area of about 75 square microns, the subsurface cisterna in each element of the double cone being around 8-10% smaller due to multiple fenestrations at the level of the paraboloid.