Table 1.

Classification of VTA cells by tyrosine hydroxylase immunolabeling and physiology

Tyrosine hydroxylase (TH) immunolabelingVoltage sag (n = 104)No voltage sag (n = 8)Intermediate voltage sag (n = 12)
TH-positive (n = 27)n  = 23n  = 2n  = 2
TH-negative (n = 16)n  = 13n  = 3
Soma not recovered (n = 13)n  = 12n  = 1
Not tested (n = 68)n  = 56n  = 6n  = 6
  • Characterization of VTA cells. Numbers of cells showing positive staining for tyrosine hydroxylase, where tested, and the presence of the conductance IH, indicated by a depolarizing voltage sag in response to injections of hyperpolarizing current (see Materials and Methods). Total number of cells, 124.