Administration of clozapine to a mother rat potentiates pup ultrasonic vocalization in response to separation and re-separation: contrast with haloperidol

Abstract

The present study examined how haloperidol (typical) and clozapine (atypical) treatment to mother rats affected their pups' ultrasonic vocalization (USV) response to maternal separation and re-separation (termed "maternal potentiation"). Clozapine (10 mg/kg, sc) but not haloperidol (0.2 mg/kg, sc) significantly enhanced the maternal potentiation of 40 kHz USVs in pups that were briefly reunited with their dams. This novel paradigm provides an indirect way of assessing the impact of antipsychotic treatment on the quality of maternal care. It may also be useful in examining the impact of antipsychotic treatment on social bonding between infants and mothers.

Figure 1

Exemplary spectrograms of the three types of pup ultrasonic vocalizations (from left to right): Long, short and Frequency-modulated. The “x” axis represents time (duration in milliseconds), and the “y” axis represents acoustic frequency (kHz).

Figure 2

Effects of clozapine treatment (10.0 mg/kg, sc) on the “Long” (A), “Short” (B) and “Frequency-modulated” USV (C) in pups that were either reunited with their mothers (i.e. “CLZ-maternal” and “VEH-Maternal”) or remained isolated (i.e. “CLZ-Control” and “VEH-Control”). Pup USVs were recorded for three minutes in two tests on postnatal day 10, 12 and 14. * P < 0.05 significant group difference between CLZ-Maternal and other groups.

Figure 2

Effects of clozapine treatment (10.0 mg/kg, sc) on the “Long” (A), “Short” (B) and “Frequency-modulated” USV (C) in pups that were either reunited with their mothers (i.e. “CLZ-maternal” and “VEH-Maternal”) or remained isolated (i.e. “CLZ-Control” and “VEH-Control”). Pup USVs were recorded for three minutes in two tests on postnatal day 10, 12 and 14. * P < 0.05 significant group difference between CLZ-Maternal and other groups.

Figure 3

Effects of haloperidol treatment (0.2 mg/kg, sc) on the “Long” (A), “Short” (B) and “Frequency-modulated” USV (C) in pups that were either reunited with their mothers (i.e. “HAL-maternal” and “VEH-Maternal”) or remained isolated (i.e. “HAL-Control” and “VEH-Control”). Pup USVs were recorded for three minutes in two tests on postnatal day 10, 12 and 14. * P < 0.05 significant group difference between HAL-Maternal and VEH-Control.

Figure 3

Effects of haloperidol treatment (0.2 mg/kg, sc) on the “Long” (A), “Short” (B) and “Frequency-modulated” USV (C) in pups that were either reunited with their mothers (i.e. “HAL-maternal” and “VEH-Maternal”) or remained isolated (i.e. “HAL-Control” and “VEH-Control”). Pup USVs were recorded for three minutes in two tests on postnatal day 10, 12 and 14. * P < 0.05 significant group difference between HAL-Maternal and VEH-Control.