Levels of βIII tubulin, TH and proNGF were analyzed by Western blot in control pineal lysates from animals reared in LD conditions (n=3) (lanes 4–6), or maintained for 12 days in constant light (n=3) (lanes 1–3, 7 and 8) and received 12 consecutive daily injections of vehicle (lanes 1–3) or isoproterenol (ISO; lanes 7 and 8) (n=3, two lanes were shown). βIII tubulin, TH and proNGF are decreased in animals maintained in LL (lanes 1–3) compared to animals reared in LD (lanes 4–6). This decrease is rescued with 12 daily administrations of ISO (lanes 7 and 8). AANAT, which is found only during the dark phase of the light cycle and is induced by the activation of pineal β-adrenergic receptors, was monitored to confirm the effect of light exposure and efficacy of the ISO injection. All animals were sacrificed at ZT18.