The ontogeny of delta-9-tetrahydrocannabinol responsiveness in the rabbit.

An autosomal recessive condition (thc/thc) in our closed colony of New Zealand White rabbits (Uaz:NZW-thc) results in nonfatal, behavioral convulsions following intravenous (i.v.) injections of delta-9-tetrahydrocannabinol (THC) and other psychoactive cannabinoids of marijuana. The ontogeny of the convulsive response was evaluated in potential THC-seizure-susceptible (SS) rabbits from postnatal Days (PN) 15-548. Ages of nonsusceptibility (PN 15-23), partial susceptibility (PN 24-38), and complete susceptibility (PN 39-548) were found. Also, open-field activity was determined in PN 14-25 THC-SS and THC-seizure-resistant (SR) rabbits. Administration of THC during the seizure-insensitive period resulted in genotype-dependent alternations in photocell activity and sprawling.