Effects of Beta; 1-adrenoceptors in the Basolateral Amygdala on Spatial Memory, Passive Avoidance, Long-term Potentiation and Neuronal Arborization in the Hippocampal CA1 Region in Response to Unavoidable Stress

Abstract Norepinephrine in the basolateral amygdala (BLA) plays a pivotal role in mediating the effects of stress on memory functions in the hippocampus, however, the functional contribution of β1-adrenergic receptors on the BLA inputs to the CA1 region of hippocampus and memory function are not well understood. In the present study the role of β1-adrenoreceptor in the BLA on memory, neuronal arborization and long-term potentiation (LTP) in the CA1 region of hippocampus was examined by infusion the β1-adrenoreceptor agonist (Dobutamine; 0.5µl/side) or antagonist (Atenolol; 0.25µL/side) bilaterally into the BLA before foot-shock stress. Passive avoidance test results showed that Step-through latency time was significantly decreased in the stress group rats one, four and seven days after the stress, which intra-BLA injection of Atenolol or Dobutamine before stress couldn't attenuate this reduction. Barnes-maze results revealed that infusion of Dobutamine and Atenolol significantly reduced spatial memory indicators such as increased latency time, the number of errors and the distance traveling to achieve the target hole in the stress group. These learning impairments in stress rats correlated with a reduction of LTP in hippocampal CA1 synapses in-vivo, which infusion of Dobutamine and Atenolol couldn't attenuate the population spike amplitude and mean-field excitatory postsynaptic potentials (fEPSP) slope reduction induced by stress. Also, the Golgi-Cox staining demonstrated that infusion of Atenolol attenuated stress decreased CA1 region dendritic and axonal arborization. These results suggest that β1-adrenergic receptors activation or block seem to exacerbate stress-induced hippocampal memory deficits and this effect is independent of CA1 LTP modulation.

The reproductive biology of the Caspian green lizard, Lacerta strigata (Sauria: Lacertidae) in Iran / La biología reproductiva de la lagartija verde del Mar Caspio, Lacerta strigata (Sauria: Lacertidae) en Iran

The Caspian Green Lizard, Lacerta strigata Eichwald, 1831, is a member of the Lacertidae family distributed in the Caspian coast of northern Iran. The specimens were found in coastal dunes, hilly areas and pastureland containing some shrubby cover. In this research, the reproductive biology of this species was studied from April 20 to September 5, 2013. Forty eight adult specimens including 24 females and 24 males were collected by hand at midday from three sampling stations (Goharbaran, Ab-Bandansar and Ab-Bandankesh) of Sari County, located in Mazandaran Province of Iran. Ovaries and testes were removed and processed for histological and morphometric studies. In females, there were 6­17 follicles in each ovary. Totally, 6­10 oviductal eggs were observed in mature females. The oogenic and spermatogenic cycle begins from late March, mating starts from early May, with oviposition occurring from late May to late June, with the possibility of producing a secondary clutch later in the season. In males, the mean number and mean diameter of seminiferous tubules were 86.95 and 190.4750 microns, respectively. The mean diameter of tunica albuginea, germinal layer and lumen were 18.75, 69.79 and 144.27 microns, respectively. Maximum reproductive activity occurs from early May to early June, reduces from early July and ends in August. Hence, oogenesis and spermatogenesis occurs from April through July, L. strigata follows a seasonal reproductive cycle with associated type.

La lagartija verde, Lacerta strigata Eichwald, 1831 es un miembro de la familia Lacertidae distribuido en la costa del mar Caspio en el norte de Irán. Los especímenes se encontraron en las dunas costeras, zonas de colinas y pastos que contienen algo de cubierta arbustiva. En esta investigación, la biología reproductiva de esta especie fue estudiada del 20 de abril al 5 de septiembre de 2013. Cuarenta y ocho ejemplares adultos, incluyendo 24 hembras y 24 machos fueron recogidos a mano al mediodía en tres estaciones de muestreo (Goharbaran, Ab-Bandansar y AB- Bandankesh) del condado de Sari, ubicado en la provincia Mazandaran de Irán. Los ovarios y los testículos fueron retirados y procesados para estudios histológicos y morfométricos. En las hembras, se observaron 6­17 folículos en cada ovario. En total, se encontraron 6­10 huevos en los oviductos de hembras maduras. El ciclo oogénico y la espermatogénesis comenzaron a partir de fines de marzo, el apareamiento se inició desde principios de mayo con la oviposición ocurriendo desde fines de mayo hasta fines de junio. Las hembras depositan 6­10 huevos por puesta, con la posibilidad de producir una segunda puesta más adelante en la temporada. En los machos, el número medio y el diámetro medio de los túbulos seminíferos fueron 86,95 y 190,475 micras, respectivamente. El diámetro medio de túnica albugínea, la capa germinal y lumen fueron de 18,75, 69,79 y 144,27 micras, respectivamente. La actividad reproductiva máxima se produce desde principios de mayo hasta principios de junio, se reduce desde principios de julio y termina en agosto. Por lo tanto, la ovogénesis y espermatogénesis se producen a partir de abril a julio, L. strigata sigue una temporada ciclo reproductivo con tipo asociado.