Fig. 9. Light microscopy of dopamine-stimulated cement glands. Cement glands were fixed at various times during dopamine exposure, and sections were cut. Toluidine Blue-stained sections were examined under the microscope. Note the absence of vacuoles in the control gland (A) and the appearance of vacuoles after 4 min exposure to dopamine (B), which increase in number after 10 min exposure (C).