The selective response of the protocerebral neurosecretory cells of the Cerambyx cerdo larvae to the effect of different factors

Abstract

1. 1. The effect of temperature, peanut oil and juvenile hormone (JH) on the protocerebral neurosecretory cells (NSC) of the larval Cerambyx cerdo was investigated. 2. 2. Winter larvae (body wt 3.5–4.0g), previously acclimated to a temperature of 10°C (control) and then to that of 23°C were divided into three experimental groups: one group was only temperature treated, the other two groups were injected with peanut oil and/or JH. 3. 3. Four subtypes of PF positive protocerebral NSC were identified: A1 and A2 in the medial and L1 and L2 in the lateral NSC group. 4. 4. At a temperature of 23°C an increase in the synthesis of the neurosecretory material (NSM) in A1 and A2 cells was observed. 5. 5. Decreased rate of synthesis of PF stainable material was recorded in L1 cells, whereas L2 cells were not affected by the above temperature. 6. 6. Injection of peanut oil into larvae evokes a decrease in the synthetic activity of all the cells studied, but an increase in the rate of NSM transport. 7. 7. The most evident effect of the JH is expressed in the A1 cells whose rate of production and transport of NSM is lower.