Pharmacological antagonism of the CRF1 receptor eliminates morphine-induced sociability deficits in male, but not in female, mice.

(A) Experimental procedure. Male and female C57BL/6J mice were injected per os (p.o.) with either vehicle or the CRF1 receptor-preferring antagonist antalarmin (20 mg/kg). One hour later, they were injected intraperitoneally (i.p.) with either saline or morphine (2.5 mg/kg) and tested in the three-chamber task for sociability. Time (s) spent in the regions of interest (ROIs, side half-chambers) of the three-chamber apparatus by male (B and C) and female (E and F) mice during the (B and E) habituation or the (C and F) sociability phase of the test. During the habituation phase, the ROIs contained empty wire cages; during the sociability phase, the wire cages contained an unfamiliar same-sex mouse or an object (A). Sociability ratio (%) displayed by (D) male and (G) female mice. The number of animals within each experimental group is reported in Table S1A. Values represent mean±S.E.M. *P<0.05, **P<0.005, ***P<0.0005.

Pharmacological antagonism of the CRF1 receptor eliminates neuronal firing induced by morphine in male, but not in female, mice.

(A) Experimental procedure. Male and female C57BL/6J mice were injected per os (p.o.) with either vehicle or the CRF1 receptor-preferring antagonist antalarmin (20 mg/kg). One hour later, they were injected intraperitoneally (i.p.) with either saline or morphine (2.5 mg/kg). Ten minutes after, brains were removed and cell-attached patch-clamp recordings of paraventricular nucleus of the hypothalamus (PVN) neurons performed from brain slices. Scale bars: 200 and 10 µm. Firing frequency (Hz) of PVN neurons displayed by (B) male and (D) female mice treated with either vehicle or antalarmin followed by either saline or morphine. Images showing electrophysiological recordings from PVN neurons of the four (C) male and the four (E) female experimental groups. The number of total patched and recorded cells within each experimental group is reported in Table S1C. Values represent mean±SEM. **P<0.005, ***P<0.0005.

Genetic inactivation of the CRF1 receptor eliminates morphine-induced sociability deficits and neuronal firing.

(A) Experimental procedure. Male CRF1+/+, CRF1+/− and CRF1−/− mice were injected intraperitoneally (i.p.) with either saline or morphine (0.625 mg/kg) and tested in the three-chamber task for sociability. Additional groups of male CRF1+/+, CRF1+/− and CRF1−/− mice were injected with either saline or morphine (0.625 mg/kg) and cell-attached patch-clamp recordings of paraventricular nucleus of the hypothalamus (PVN) neurons performed from brain slices. Time (s) spent in the regions of interest (ROIs, side half-chambers) of the three-chamber apparatus (see Fig. 1A) during the (B) habituation and the (C) sociability phase of the test, (D) sociability ratio (%) and (E) firing frequency (Hz) of PVN neurons by saline- or morphine-treated CRF1+/+, CRF1+/− and CRF1−/− mice. (F) Images showing electrophysiological recordings from PVN neurons of the six experimental groups. The number of animals and the number of patched and recorded cells within each experimental group is reported in Table S1B. Values represent mean±SEM. *P<0.05, **P<0.005, ***P<0.0005.

Pharmacological antagonism of the CRF1 receptor eliminates morphine-induced firing of oxytocin-expressing neurons in male, but not in female, mice.

(A) Immunohistochemical images of a paraventricular nucleus of the hypothalamus (PVN) neuron co-expressing oxytocin (OXY+) and arginine-vasopressin (AVP+). Scale bar: 20 µm. Number of patched and recorded PVN neurons expressing OXY and/or AVP or neither of the two neuropeptides in (B) male and (E) female C57BL/6J mice. Firing frequency (Hz) of PVN neurons expressing OXY and/or AVP in (C and D) male and (F and G) female C57BL/6J mice treated with either vehicle or antalarmin (20 mg/kg) followed by either saline or morphine (2.5 mg/kg), as shown in Fig. 2A. The number of patched and recorded cells within each experimental group is reported in Table S1C. Values represent mean±SEM. *P<0.05, **P<0.005, ***P<0.0005.