Manuscript accepted in Psychopharmacology

Abraham Palmer Publications

The manuscript titled "High Incidence of Estrous Cycle Irregularities in Heterogeneous Stock (HS) Rats is Associated with Footshock-Resistant Cocaine Intake" was accepted for publication in Psychopharmacology.

Authors: Elizabeth A. Sneddon, Supakorn Chonwattanagul, Kathleen Bai, Pranav H. Kurup, Sonja L. Plasil, Michelle R. Doyle*, Sélène Zahedi, Sierra Simpson, Benjamin C. Sichel, Dyar N. Othman, Molly Brennan, Abraham A. Palmer, Marsida Kallupi, Lieselot L.G. Carrette, Giordano de Guglielmo, & Olivier George

(Current and past* Palmer Lab members)

Congratulations!

Psychopharmacology, 2026, in press (online ahead of print)

DOI: 10.1007/s00213-026-07041-8

Irregular estrous cycling may influence cocaine vulnerability.
(A) Timeline of Experiment 1. (B) Cocaine infusions across short access (ShA) and long access (LgA) sessions (n = 298). (C) Number of infusions by estrous cycle phase during ShA10 (n = 178). (D) Number of infusions by estrous cycle phase distribution during long access LgA 14 (n = 238). (E) Regardless of the collapsed estrous phase, subjects earned more cocaine infusions during LgA vs. ShA sessions. (F) The collapsed estrous phases are not associated with cocaine infusions during progressive ratio 1 (PR01, n = 151). (G) Visual representation of cytology in each phase of the estrous cycle: diestrus, proestrus, estrus, and metestrus. (H) Visualization of 24-h cycling in a subset of HS rats (n = 39). Regular cycling is outlined by a bolded line. (I) Percentage of rats with regular vs. irregular cycling. (J) Self-administration of rats showing regular (n = 7) and irregular (n = 14) cycling patterns across ShA and LgA sessions. (K) Correlation between irregularity index and average infusions on ShA sessions 1–4 (p = 0.057). (L) No correlation between the irregularity index and cocaine infusions during the last four sessions of LgA. Cycling irregularities were not associated with cocaine infusions during (M) ShA7-10, (N) LgA11-14, (O) PR01, or (P), PR02. (Q) Rats with severe cycling irregularities infused more cocaine during the shock session. (* p < 0.05, ** p < 0.001, or **** p < 0.001, main effect One- or Two-Way ANOVA. # p < 0.05, ## p < 0.001, or ### p < 0.001, session compared to session 1, Dunnett’s)

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